MR. JUSTICE POWELL delivered the opinion of the Court.This case presents issues concerning the construction of Title III of the Omnibus Crime Control and Safe Streets Act of 1968, 18 U.S.C. §§ 2510-2520.  Specifically, we must decide whether 18 U.S.C. § 2518(1)(b)(iv), which requires the Government to include in its wiretap applications "the identity of the person, if known, committing the offense and whose communications are to be intercepted," is satisfied when the Government identifies only the "principal targets" of the intercept.  Second, we must decide whether the Government has a statutory responsibility to inform the issuing judge of the identities of persons whose conversations were overheard in the course of the interception, thus enabling him to decide whether they should be served with notice of the interception pursuant to 18 U.S.C. § 2518(8)(d).  And finally, we must determine whether failure to comply fully with these statutory provisions requires suppression of evidence under 18 U.S.C. § 2518(10)(a).IOn November 28, 1972, a special agent of the Federal Bureau of Investigation applied to the United States District Court for the Northern District of Ohio for an order authorizing a wiretap interception in accordance with Title III. [Footnote 1]  The application requested authorization to intercept Page 429 U. S. 417 gambling-related communications over two telephones at one address in North Olmstead, Ohio, and two other telephones at a home in Canton, Ohio.  The accompanying affidavit recited that the telephones were being used by Albert Kotoch, Joseph Spaganlo, and George Florea to conduct an illegal gambling business, and that in conducting that business they Page 429 U. S. 418 would place calls to and receive calls from various persons, three of whom were also named in the wiretap application. [Footnote 2]  The affiant also stated that the Government's informants would refuse to testify against the persons named in the application, that telephone records alone would be insufficient to support a gambling conviction, and that normal investigative techniques were unlikely to be fruitful.  Pursuant to the Government's request, the District Court authorized for a period of 15 days the interception of gambling-related wire communications of Kotoch, Spaganlo, Florea, three named individuals other than the respondents, and "others, as yet unknown," to and from the four listed telephones. [Footnote 3] Page 429 U. S. 419During the course of the wiretap, the Government learned that respondents Donovan, Robbins, and Buzzacco were discussing illegal gambling activities with the named subjects.  On December 26, 1972, the Government applied for an extension of the initial intercept order. [Footnote 4]  This time it sought authorization to intercept gambling-related conversations of Kotoch, Spaganlo, Florea, two other named individuals, and "others as yet unknown," but it did not identify respondents Donovan, Buzzacco, and Robbins in this second application. [Footnote 5]  Page 429 U. S. 420 The District Court again authorized interception of gambling-related conversations for a maximum of 15 days.On February 21, 1973, the Government submitted to the District Court a proposed order giving notice of the interceptions to 37 persons, a group which the Government apparently thought included all individuals who could be identified as having discussed gambling over the monitored telephones. [Footnote 6]  The District Court signed the proposed order, and an inventory notice was served on the listed persons, including respondents Donovan, Buzzacco, and Robbins.  On September 11, 1973, after the Government submitted the names of two additional persons whose identities allegedly had been omitted inadvertently from the initial list, the District Court entered an amended order giving notice to those individuals.  As a result of what the Government labels "administrative oversight," respondents Merlo and Lauer were not included in either list of names, and were never served with inventory notice. [Footnote 7] Page 429 U. S. 421On November 1, 1973, an indictment was returned in the United States District Court for the Northern District of Ohio charging Kotoch, Spaganlo, the five respondents, and 10 other individuals with conspiracy to conduct and conducting a gambling business in violation of 18 U.S.C. §§ 371 and 1955.  The five respondents filed motions to suppress evidence derived from the wire interception.  After an evidentiary hearing on the motions, the District Court suppressed as to respondents Donovan, Robbins, and Buzzacco all evidence derived from the December 26 intercept order on the ground that failure to identify them by name in the application and order of that date violated 18 U.S.C. §§ 2518(1)(b)(iv) and 2518(4)(a).  With respect to Merlo and Lauer, who were not known to the Government until after the December 26 application, the District Court suppressed all evidence derived from both intercept orders on the ground that they had not been served with inventory notice.The Court of Appeals for the Sixth Circuit affirmed. 513 F.2d 337 (1975). [Footnote 8]  On the identification issue, the court held that the wiretap application must identify every person whose conversations relating to the subject criminal activity the Government has probable cause to believe it will intercept.  Agreeing with the District Court that at the time of the December 26 application the Government had probable cause to believe that it would overhear Donovan, Robbins, and Buzzacco "committing the offense," the Court of Appeals affirmed the suppression of evidence derived from Page 429 U. S. 422 the December 26 order.  On the notice question, it held that the Government has an implied statutory duty to inform the issuing judge of the identities of the parties whose conversations were overheard so that he can determine whether discretionary inventory notice should be required. [Footnote 9]  Because the Government had failed to perform this duty with respect to Merlo and Lauer, the Court of Appeals affirmed the District Court's order suppressing evidence derived from both intercept orders.  The court found it unnecessary to determine whether the failure to identify respondents Donovan, Robbins, and Buzzacco in the December 26 application and to name respondents Merlo and Lauer in the proposed inventory notice orders was inadvertent or purposeful, since the mere fact of omission was sufficient to require suppression under 18 U.S.C. § 2518(10)(a). [Footnote 10]We granted certiorari to resolve these issues, which concern the construction of a major federal statute, 424 U.S. 907, and now reverse.IIThe United States contends that § 2518(1)(b)(iv) requires that a wiretap application identify only the principal target of the interception, and that § 2518(8)(d) does not require the Government to provide the issuing judge with a list of all identifiable persons who were overheard in the Page 429 U. S. 423 course of an authorized interception.  We think neither contention is sound.AWe turn first to the identification requirements of § 2518(1)(b)(iv).  That provision requires a wiretap application to specify "the identity of the person, if known, committing the offense and whose communications are to be intercepted."  In construing that language, this Court already has ruled that the Government is not required to identify an individual in the application unless it has probable cause to believe (i) that the individual is engaged in the criminal activity under investigation and (ii) that the individual's conversations will be intercepted over the target telephone.  United States v. Kahn, 415 U. S. 143 (1974).  The question at issue here is whether the Government is required to name all such individuals. [Footnote 11] Page 429 U. S. 424The United States argues that the most reasonable interpretation of the plain language of the statute is that the application must identify only the principal target of the investigation, who "will almost always be the individual whose phone is to be monitored." [Footnote 12]  Brief for United States 18. Under this interpretation, if the Government has reason to believe that an individual will use the target telephone to place or receive calls, and the Government has probable cause to believe that the individual is engaged in the criminal activity under investigation, the individual qualifies as a principal target and must be named in the wiretap application.  On the other hand, an individual who uses a different telephone to place calls to or receive calls from the target telephone is not a principal target even if the Government has probable cause to believe that the individual is engaged in the criminal activity under investigation.  In other words, whether one is a principal target of the investigation depends on whether one operates the target telephone to place or receive calls. [Footnote 13]Whatever the merits of such a statutory scheme, we find little support for it in the language and structure of Title III or in the legislative history.  The statutory language itself refers only to "the person, if known, committing the Page 429 U. S. 425 offense and whose communications are to be intercepted."  That description is as applicable to a suspect placing calls to the target telephone as it is to a suspect placing calls from that telephone.  It is true, as the United States suggests, that, when read in the context of the other subdivisions of § 2518(1)(b), an argument can be made that Congress focused in subdivision (iv) on the primary user of the target telephone.  But it is also clear from other sections of the statute that Congress expected that wiretap applications would name more than one individual.  For example, Title III requires that inventory notice be served upon "the persons named in the order or the application."  18 U.S.C. § 2518(8)(d) (emphasis added).  And § 2518(1)(e) requires that an intercept application disclose all previous intercept applications "involving any of the same persons . . . specified in the application" (emphasis added).  It may well be that Congress anticipated that a given application would cover more than one telephone or that several suspects would use one telephone, and that an application for those reasons alone would require identification of more than one individual.  But nothing on the face of the statute suggests that Congress intended to remove from the identification requirement those suspects whose intercepted communications originated on a telephone other than that listed in the wiretap application. [Footnote 14] Page 429 U. S. 426Nor can we find support in the legislative history for the "principal target" interpretation. Title III originated as a combination of S. 675, the Federal Wire Interception Act, which was introduced by Senator McClellan several months prior to this Court's decision in Berger v. New York, 388 U. S. 41 (1967), and S. 2050, the Electronic Surveillance Control Act of 1967, introduced by Senator Hruska a few days after the Berger decision.  S.Rep. No. 1097, 90th Cong., 2d Sess., 66 (1968).  Both bills required that wiretap applications include a full and complete statement of the facts and circumstances relied upon by the applicant and specification of the nature and location of the communication facilities involved.  Although neither bill contained an express identification requirement such as that at issue here, both bills required the application to include a"full and complete statement of the facts concerning all previous applications . . . involving any person named in the application as committing, having committed, or being about to commit an offense."Hearings Before the Subcommittee on Criminal Laws and Procedures of the Senate Committee on the Judiciary on Controlling-Crime Through More Effective Law Enforcement, 90th Cong., 1st Sess., 77, § 8(a)(3), and 1006, § 2518(4)(a) (1967) (emphasis added).  Thus, even at this early stage, it was recognized that an application could identify several individuals, and there is no indication that the identification would be limited to principal targets.  S. 917 combined the major provisions of S. 675 and S. 2050 and eventually was enacted.  While it was pending before the Senate Judiciary Committee, this Court decided Katz v. United States, 389 U. S. 347 (1967).  S. 917 was then redrafted to conform to Katz as well as Berger, and the identification provision was added at that time.  The Senate Report states that the requirements set forth in the various Page 429 U. S. 427 subdivisions of  2518(1)(b), including the identification requirement at issue here, were intended to "reflect . . . the constitutional command of particularization."  S.Rep. No. 1097, supra at 101, citing Berger v. New York, supra, at  388 U. S. 58-60, and Katz v. United States, supra at  389 U. S. 354-356.  The United States now contends that, although it may be that Congress read Berger and Katz to require, as a constitutional matter, that the subject of the surveillance be named if known, Congress would hardly have read those cases as requiring the naming of all parties likely to be overheard. [Footnote 15]  Brief for United States 226.  But to the extent that Congress thought it was meeting the constitutional commands of particularization established in Berger and Katz, Congress may have read those cases as mandating a broad identification requirement.  The statute that we confronted in Berger required identification of "the person or persons" whose communications were to be overheard.  388 U.S. at  388 U. S. 59.  And we expressly noted that that provision "[did] no more than identify the person whose constitutionally protected area is to be invaded. . . ."  Ibid.  Given the statute at issue in Berger and our comment upon it, Congress may have concluded that the Constitution required the naming, in a wiretap application, of all suspects rather than just the primary user. [Footnote 16] Page 429 U. S. 428In any event, for our present purposes, it is unnecessary to speculate as to exactly how Congress interpreted Berger and Katz with respect to the identification issue.  It is sufficient to note that, in response to those decisions Congress included an identification requirement which, on its face, draws no distinction based on the telephone one uses, and the United States points to no evidence in the legislative history that supports such a distinction.  Indeed, the legislative materials apparently contain no use of the term "principal target" or any discussion of a different treatment based on the telephone from which a suspect speaks. [Footnote 17]  We therefore conclude that a wiretap application must name an individual if the Government has probable cause to believe that the individual is engaged in the criminal activity under investigation and expects to intercept the individual's conversations over the target telephone.BThe other statutory provision at issue in this case is 18 U.S.C. § 2518(8)(d), which provides that the judge shall cause to be served on the persons named in the order or application an inventory, which must give notice of the entry of the order or application, state the disposition of Page 429 U. S. 429 the application, and indicate whether communications were intercepted. [Footnote 18]  Although the statute mandates inventory notice only for persons named in the application or the order, the statute also provides that the judge may order similar notice to other parties to intercepted communications if he concludes that such action is in the interest of justice. [Footnote 19]  Observing that this notice provision does not expressly require law enforcement authorities routinely to supply the judge with specific information upon which to exercise his discretion, the United States contends that it would be inappropriate to read such a requirement into the statute, since the judge has the option of asking the law enforcement authorities for whatever information he requires.Our reading of the legislative history of the discretionary notice provision in light of the purposes of Title III leads us to reject the Government's interpretation.  As reported from the Judiciary Committee, § 2518(8)(d) contained only a provision mandating notice to the persons named in the application or the order; the discretionary notice provision was added by amendment on the floor of the Senate.  In introducing that amendment, Senator Hart explained its purpose:"The amendment would give the judge who issued the order discretion to require notice to be served on other parties to intercepted communications, even though such Page 429 U. S. 430 parties are not specifically named in the court order.  The Berger and Katz decisions established that notice of surveillance is a constitutional requirement of any surveillance statute.  It may be that the required notice must be served on all parties to intercepted communications.  Since legitimate interests of privacy may make such notice to all parties undesirable, the amendment leaves the final determination to the judge."114 Cong.Rec. 14485-14486 (1968). [Footnote 20]In deciding whether legitimate privacy interests justify withholding inventory notice from parties to intercepted conversations, a judge is likely to require information and assistance beyond that contained in the application papers and the recordings of intercepted conversations made available by law enforcement authorities.  No purpose is served by holding that those authorities have no routine duty to supply the judge with relevant information.  The Court of Appeals for the Ninth Circuit recently confronted this problem of dual responsibility, and we adopt the balanced construction that court placed on § 2518(8)(d):"To discharge this obligation, the judicial officer must have, at a minimum, knowledge of the particular categories into which fall all the individuals whose conversations Page 429 U. S. 431 have been intercepted.  Thus, while precise identification of each party to an intercepted communication is not required, a description of the general class, or classes, which they comprise is essential to enable the judge to determine whether additional information is necessary for a proper evaluation of the interests of the various parties.  Furthermore, although the judicial officer has the duty to cause the filing of the inventory [notice], it is abundantly clear that the prosecution has greater access to and familiarity with the intercepted communications.  Therefore we feel justified in imposing upon the latter the duty to classify all those whose conversations have been intercepted, and to transmit this information to the judge.  Should the judge desire more information regarding these classes in order to exercise his [statutory] § 2518(8)(d) discretion, . . . the government is [also] required to furnish such information as is available to it."United States v Chun, 503 F.2d 533, 540 (1974).  (Footnote omitted.)  We agree with the Ninth Circuit that this allocation of responsibility best serves the purposes of Title III. [Footnote 21]Currently, the policy of the Justice Department is to provide the issuing judge with the name of every person who has been overheard as to whom there is any reasonable possibility of indictment.  Brief for United States 39.  Because it fails to assure that the necessary range of information Page 429 U. S. 432 will be before the issuing judge, this policy does not meet the test set out in Chun.  Moreover, where, as here, the Government chooses to supply the issuing judge with a list of all identifiable persons rather than a description of the classes into which those persons fall, the list must be complete.  Applying these principles, we find that the Government did not comply adequately with § 2518(8)(d), since the names of respondents Merlo and Lauer were not included on the purportedly complete list of identifiable persons submitted to the issuing judge.IIIWe turn now to the question whether the District Court properly suppressed evidence derived from the wiretaps at issue solely because of the failure of the law enforcement authorities to comply fully with the provisions of §§ 2518(1)(b)(iv) and 2518(8)(d).  Section 2515 expressly prohibits the use at trial, and at certain other proceedings, of the contents of any intercepted wire communication or any evidence derived therefrom "if the disclosure of that information would be in violation of this chapter."  The circumstances that trigger suppression under § 2515 are, in turn, enumerated in § 2518(10)(a):"(i) the communication was unlawfully intercepted;""(ii) the order of authorization or approval under which it was intercepted is insufficient on its face; or""(iii) the interception was not made in conformity with the order of authorization or approval."There is no basis on the facts of this case to suggest that the authorization orders are facially insufficient, or that the interception was not conducted in conformity with the orders.  Thus, only § 2518(10)(a)(i) is relevant:  were the communications "unlawfully intercepted" given the violations of §§ 2518(1)(b)(iv) and 2518(8)(d)? [Footnote 22] Page 429 U. S. 433Resolution of that question must begin with United States v. Giordano, 416 U. S. 505 (1974), and United States v. Chavez, 416 U. S. 562 (1974).  Those cases hold that"[not] every failure to comply fully with any requirement provided in Title III would render the interception of wire or oral communications 'unlawful.'"Id. at  416 U. S. 574-575.  To the contrary, suppression is required only for a"failure to satisfy any of those statutory requirements that directly and substantially Page 429 U. S. 434 implement the congressional intention to limit the use of intercept procedures to those situations clearly calling for the employment of this extraordinary investigative device."United States v. Giordano, supra at  416 U. S. 527.Giordano concerned the provision in Title III requiring that an application for an intercept order be approved by the Attorney General or an Assistant Attorney General specially designated by the Attorney General.  Concluding that Congress intended to condition the use of wiretap procedures on the judgment of senior officials in the Department of Justice, the Court required suppression for failure to comply with the approval provision.  Chavez concerned the statutory requirement that the application for an intercept order specify the identity of the official authorizing the application.  The problem in Chavez was one of misidentification; although the application had in fact been authorized by the Attorney General, the application erroneously identified an Assistant Attorney General as the official authorizing the application.  The Court concluded that mere misidentification of the official authorizing the application did not make the application unlawful within the meaning of § 2518(10)(a)(i), since that identification requirement did not play a "substantive role" in the regulatory system.  416 U.S. at  416 U. S. 578.In the instant case, the Court of Appeals concluded that both the identification requirement of § 2518(1)(b)(iv) and the notice requirement of § 2518(8)(d) played a "central role" in the statutory framework, and for that reason affirmed the District Court's order suppressing relevant evidence.  Although both statutory requirements are undoubtedly important, we do not think that the failure to comply fully with those provisions renders unlawful an intercept order that in all other respects satisfies the statutory requirements. Page 429 U. S. 435AAs to § 2518(1)(b)(iv), the issue is whether the identification in an intercept application of all those likely to be overheard in incriminating conversations plays a "substantive role" with respect to judicial authorization of intercept orders and consequently imposes a limitation on the use of intercept procedures.  The statute provides that the issuing judge may approve an intercept application if he determines that normal investigative techniques have failed or are unlikely to succeed and there is probable cause to believe that:  (i) an individual is engaged in criminal activity; (ii) particular communications concerning the offense will be obtained through interception; and (iii) the target facilities are being used in connection with the specified criminal activity.  §§ 2518(3)(a-d).  That determination is based on the "full and complete statement" of relevant facts supplied by law enforcement authorities.  If, after evaluating the statutorily enumerated factors in light of the information contained in the application, the judge concludes that the wiretap order should issue, the failure to identify additional persons who are likely to be overheard engaging in incriminating conversations could hardly invalidate an otherwise lawful judicial authorization.  The intercept order may issue only if the issuing judge determines that the statutory factors are present, and the failure to name additional targets in no way detracts from the sufficiency of those factors.This case is unlike Giordano, where failure to satisfy the statutory requirement of prior approval by specified Justice Department officials bypassed a congressionally imposed limitation on the use of the intercept procedure.  The Court there noted that it was reasonable to believe that requiring prior approval from senior officials in the Justice Department"would inevitably foreclose resort to wiretapping in various situations where investigative personnel would otherwise seek intercept authority from the court Page 429 U. S. 436 and the court would very likely authorize its use."416 U.S. at  416 U. S. 528.  Here, however, the statutorily imposed preconditions to judicial authorization were satisfied, and the issuing judge was simply unaware that additional persons might be overheard engaging in incriminating conversations.  In no meaningful sense can it be said that the presence of that information as to additional targets would have precluded judicial authorization of the intercept. [Footnote 23]  Rather, this case resembles Chavez, where we held that a wiretap was not unlawful simply because the issuing judge was incorrectly informed as to which designated official had authorized the application.  The Chavez intercept was lawful because the Justice Department had performed its task of prior approval, and the instant intercept is lawful because the application provided sufficient information to enable the issuing judge to determine that the statutory preconditions were satisfied. [Footnote 24] Page 429 U. S. 437Finally, we note that nothing in the legislative history suggests that Congress intended this broad identification requirement to play "a central, or even functional, role in guarding against unwarranted use of wiretapping or electronic surveillance."  United States v. Chavez, 416 U.S. at  416 U. S. 578.  Neither S. 675 nor S. 2050, the predecessor bills of S. 917, contained an identification provision.  See supra at  429 U. S. 426.  The only explanation given in the Senate Report for the inclusion of the broad identification provision was that it was intended to reflect what Congress perceived to be the constitutional command of particularization.  This explanation was offered with respect to all the information required by § 2518(1)(b) to be set out in an intercept application.  No additional guidance can be gleaned from the floor debates, since they contain no substantive discussion of the identification provision. [Footnote 25] Page 429 U. S. 438BWe reach the same conclusion with respect to the Government's duty to inform the judge of all identifiable persons whose conversations were intercepted.  As noted earlier, the version of Title III that emerged from the Senate Judiciary Committee provided only for mandatory notice to the "persons named in the order or the application."  The Senate Report detailed the purpose of that provision:"[T]he intent of the provision is that the principle of post-use notice will be retained.  This provision alone should insure the community that the techniques are reasonably employed.  Through its operation, all authorized interceptions must eventually become known at least to the subject.  He can then seek appropriate civil redress, for example, under section 2520 . . . if he feels that his privacy has been unlawfully invaded."S.Rep. No. 1097, 90th Cong., 2d Sess., 105 (1968).  The floor discussion concerning the amendment adding the provision for discretionary notice merely indicates an intent to provide notice to such additional persons as may be constitutionally required.Nothing in the structure of the Act or this legislative history suggests that incriminating conversations are "unlawfully intercepted" whenever parties to those conversations do not receive discretionary inventory notice as a result of the Government's failure to inform the District Court of their identities.  At the time inventory notice was served on the other identifiable persons, the intercept had been completed and the conversations had been "seized" under a valid intercept order.  The fact that discretionary notice reached Page 429 U. S. 439 39, rather than 41, identifiable persons does not, in itself, mean that the conversations were unlawfully intercepted. [Footnote 26]The legislative history indicates that post-intercept notice was designed instead to assure the community that the wiretap technique is reasonably employed.  But even recognizing that Congress placed considerable emphasis on that aspect of the overall statutory scheme, we do not think that post-intercept notice was intended to serve as an independent restraint on resort to the wiretap procedure.IVAlthough the Government was required to identify respondents Donovan, Robbins, and Buzzacco in the December 26 application for an extension of the initial intercept, failure to do so in the circumstances here presented did not warrant suppression under § 2518(10)(a)(i).  Nor was suppression justified with respect to respondents Merlo and Lauer simply because the Government inadvertently omitted their names from the comprehensive list of all identifiable persons whose conversations had been overheard.  We hold that this is the correct result under the provisions of Title III, but we reemphasize Page 429 U. S. 440 the suggestion we made in United States v. Chavez that"strict adherence by the Government to the provisions of Title III would nonetheless be more in  keeping with the responsibilities Congress has imposed upon it when authority to engage in wiretapping or electronic surveillance is sought."416 U.S. at  416 U. S. 580.The judgment of the Court of Appeals is reversed, and the case is remanded to that court for further proceedings consistent with this opinion.It is so ordered
U.S. Supreme CourtUnited States v. Donovan, 429 U.S. 413 (1977)United States v. DonovanNo. 75-212Argued October 13, 1976Decided January 18, 1977429 U.S. 413SyllabusTitle 18 U.S.C. § 2518(1)(b)(iv), which is part of Title III of the Omnibus Crime Control and Safe Streets Act of 1968, requires the Government to include in its wiretap applications "the identity of the person, if known, committing the offense and whose communications are to be intercepted."  Section 2518(8)(d) requires the judge to whom a wiretap application is made to cause to be served on the persons named in the wiretap order or application an inventory, which must give notice of entry of the order or application, state the disposition of the application, and indicate whether communications were intercepted, and further provides that the judge may order similar notice to other parties to intercepted communications if he concludes that such action is in the interest of justice.  Evidence derived from wiretaps must be suppressed under § 2518(10)(a)(i) if "the communication was unlawfully intercepted."  On December 26, 1972, the Government applied for an extension of an order authorizing a wiretap interception of gambling-related conversations of certain named individuals other than respondents Donovan, Robbins, and Buzzacco and "others as yet unknown" to or from four listed telephones, and the Government did not identify these respondents in the application even though it had previously learned they were discussing illegal gambling activities with the named subjects.  The District Court authorized a 15-day interception.  On February 21, 1973, the Government submitted to the court a proposed order giving notice of the interception to 37 persons, the court signed the order, and an inventory notice was served on the listed persons, including respondents Donovan, Robbins, and Buzzacco.  Subsequently, after the Government submitted the names of two additional persons whose identities allegedly had been omitted inadvertently from the initial list, the court entered an amended order giving notice to those individuals, but as a result of "administrative oversight" respondents Merlo and Lauer were not included in either list of names and were never served with an inventory notice.  Respondents, along with others, were indicted for federal gambling offenses.  On respondents' motion, the District Court suppressed as to respondents Donovan, Robbins, and Buzzacco all evidence derived from the Page 429 U. S. 414 December 26 intercept order on the ground that failure to name them in the application and order of that date violated § 2518(1)(b)(iv), inter alia, and suppressed as to respondents Merlo and Lauer all evidence derived from both intercept orders on the ground that these two respondents had not been served with an inventory notice as required by § 2518(8)(d).  The Court of Appeals affirmed.Held:1. Section 2518(1)(b)(iv) is not satisfied when the wiretap application identifies only the "principal target" (usually the individual whose phone is monitored) of the interception, but the Government is required to name all individuals who it has probable cause to believe are engaged in the criminal activity under investigation and whose conversations it expects will be intercepted over the target telephone.  Neither the language and structure of Title III nor its legislative history supports the interpretation that Congress intended to remove from the identification requirement those suspects whose intercepted communications originated on a telephone other than that listed in the wiretap application.  Pp.  429 U. S. 423-428.2. Under § 2518(8)(d), the Government has a statutory responsibility to inform the issuing judge of the identities of persons whose conversations were overheard in the course of the interception, thus enabling him to decide whether they should be served with notice of the interception.  Here the Government did not comply adequately with § 2518(8)(d), since the names of respondents Merlo and Lauer were not included on the purportedly complete list of identifiable persons submitted to the issuing judge.  Pp.  429 U. S. 428-432.3. Although the Government was required under § 2518(1)(b)(iv) to identify respondents Donovan, Robbins, and Buzzacco in the December 26 application, failure to do so under these circumstances did not warrant suppression under § 2518(10)(a)(i), since the identification in an intercept application of all those likely to be overheard in incriminating conversations does not play a "substantive role" with respect to judicial authorization of intercept orders and hence does not impose a limitation on the use of intercept procedures.  Pp.  429 U. S. 435-437.(a) Here the statutorily imposed preconditions to judicial authorization (a determination that normal investigative techniques have failed or are unlikely to succeed, and probable cause to believe that (i) an individual is engaged in criminal activity, (ii) particular communications concerning the offense will be obtained through interception, and (iii) the target facilities are being used in connection with the specified criminal activity) were satisfied, and the issuing judge was simply unaware that additional persons might be overheard engaging in incriminating Page 429 U. S. 415 conversations, the intercept being lawful because the application provided sufficient information to enable the judge to determine that the statutory preconditions were satisfied.  Pp.  429 U. S. 435-436.(b) There is nothing in the legislative history to suggest that Congress intended § 2518(1)(b)(iv)'s broad identification requirement to play "a central, or even functional, role in guarding against unwarranted use of wiretapping or electronic surveillance," United States v. Chavez, 416 U. S. 562,  416 U. S. 578.  P.  429 U. S. 437.4. Nor was suppression justified under § 2518(10)(a)(i) with respect to respondents Merlo and Lauer simply because the Government inadvertently omitted their names from the comprehensive list of all identifiable persons whose conversations had been overheard.  Pp.  429 U. S. 438-439.(a) There is nothing in the structure or legislative history of the Act to suggest that incriminating conversations are "unlawfully intercepted" whenever parties to those conversations do not receive discretionary inventory notice under § 2518(8)(d) as a result of the Government's failure to inform the court of their identities.  P.  429 U. S. 438.(b) Here, at the time inventory notice was served on the other identifiable persons, the intercept had been completed and the conversations had been "seized" under a valid intercept order, and the fact that discretionary notice reached 39, rather than 41, identifiable persons does not, in itself, mean that the conversations were unlawfully intercepted.  Pp.  429 U. S. 438-439.513 F.2d 337, reversed and remanded.POWELL, J., delivered the opinion of the Court, in which STEWART, WHITE, BLACKMUN, and REHNQUIST, JJ., joined, in all but Part II-A of which BURGER, C.J., joined, and in Parts I and II of which STEVENS, J., joined.  BURGER, C.J., filed an opinion concurring in part and concurring in the judgment, post, p.  429 U. S. 440.  MARSHALL, J., filed an opinion dissenting in part, in which BRENNAN, J., joined, post, p.  429 U. S. 445.  STEVENS, J., filed a statement concurring in part and dissenting in part, post, p.  429 U. S. 451. Page 429 U. S. 416