The Loganian Library, as he wished it to be called, was diverse.
 The catalogue of its final holdings is now lost but a partial inventory done in 1760 reveals a wide selection of books.
The book distribution by date reveals nothing out of the ordinary.
 Most were from the seventeenth century with 57 percent.
Next came those from the eighteenth century at 27 percent.
 Finally, there was a good number from the fifteenth and sixteenth centuries at 16 percent.
The collection was mostly British and northern European with 33 percent from Britain; the Netherlands, 24 percent; Germany, 17 percent; France, 13 percent; Switzerland, 9 percent; Italy, 2 percent; and others (Scandinavia, Spain, Poland, Russia, America) at 2 percent
The distribution of the books by subject in the 1760 catalogue is equally diverse with history, antiquities, geography, chronology, etc.
at 22 percent.
Religious subjects of divinity and ecclesiastical history constituted 15 percent.
 Scientific subjects such as "physick," "mathematicks", and natural history was at 16 percent.
Literary subjects such as orators, poets, fables, romances, etc.
at 14 percent with philology at 13 percent.
Philosophy, surprisingly, was only 6 percent while arts, liberal and mechanical, "magick," etc.
was 3 percent.
The remaining subjects were as follows: medicine, surgery, and "chymistry," 2 percent; law, 2 percent; voyages and travels, 1 percent; philosophical history, 1 percent, and miscellaneous, 5 percent.

Logan's library contained many 17th and 16th century classical works such as a 1615 edition of Archimedes' works, the mathematical treatise of Pappus of Alexandria printed in 1660, an Aratus of Soles from 1672, Elzevir's architecture publication of 1649 from Amsterdam, Johann Vossius' De Quatuar Artibus Popularibus published in 1650, and a 1599 edition of astronomy edited by Barthelemy Pitiscus  In one famous episode, Logan was reading a treatise on early astronomy by Johann Fabricius and read that the first printed edition of Greek astronomer Ptolemy's Almagest was printed in Greek in 1538.
 Logan was certain that it was released in an earlier Latin version, having sold it and his other books in Dublin before he left in 1699.
 Logan wrote Fabricius and politely explained his conviction.
In reply, Fabricius reaffirmed his contention and sent his own 1538 copy as proof.
 Unconvinced, Logan wrote his agent in London, explaining that he had sold his library to a bookseller who lived on Castle Street and to see if he knew of the book's location.
 His agent was successful in finding the book and sent to Logan where it was confirmed that it was a Latin edition of the Almagest published in 1515.
Such was the strength of Logan's bibliographic mind as professed by Benjamin Franklin.
The Loganian Library, as he wished it to be called, was diverse.  The catalogue of its final holdings is now lost but a partial inventory done in 1760 reveals a wide selection of books. The book distribution by date reveals nothing out of the ordinary.  Most were from the seventeenth century with 57 percent. Next came those from the eighteenth century at 27 percent.  Finally, there was a good number from the fifteenth and sixteenth centuries at 16 percent. The collection was mostly British and northern European with 33 percent from Britain; the Netherlands, 24 percent; Germany, 17 percent; France, 13 percent; Switzerland, 9 percent; Italy, 2 percent; and others (Scandinavia, Spain, Poland, Russia, America) at 2 percent
The distribution of the books by subject in the 1760 catalogue is equally diverse with history, antiquities, geography, chronology, etc. at 22 percent. Religious subjects of divinity and ecclesiastical history constituted 15 percent.  Scientific subjects such as "physick," "mathematicks", and natural history was at 16 percent. Literary subjects such as orators, poets, fables, romances, etc. at 14 percent with philology at 13 percent. Philosophy, surprisingly, was only 6 percent while arts, liberal and mechanical, "magick," etc. was 3 percent. The remaining subjects were as follows: medicine, surgery, and "chymistry," 2 percent; law, 2 percent; voyages and travels, 1 percent; philosophical history, 1 percent, and miscellaneous, 5 percent.
Logan's library contained many 17th and 16th century classical works such as a 1615 edition of Archimedes' works, the mathematical treatise of Pappus of Alexandria printed in 1660, an Aratus of Soles from 1672, Elzevir's architecture publication of 1649 from Amsterdam, Johann Vossius' De Quatuar Artibus Popularibus published in 1650, and a 1599 edition of astronomy edited by Barthelemy Pitiscus  In one famous episode, Logan was reading a treatise on early astronomy by Johann Fabricius and read that the first printed edition of Greek astronomer Ptolemy's Almagest was printed in Greek in 1538.  Logan was certain that it was released in an earlier Latin version, having sold it and his other books in Dublin before he left in 1699.  Logan wrote Fabricius and politely explained his conviction. In reply, Fabricius reaffirmed his contention and sent his own 1538 copy as proof.  Unconvinced, Logan wrote his agent in London, explaining that he had sold his library to a bookseller who lived on Castle Street and to see if he knew of the book's location.  His agent was successful in finding the book and sent to Logan where it was confirmed that it was a Latin edition of the Almagest published in 1515. Such was the strength of Logan's bibliographic mind as professed by Benjamin Franklin.
James Logan (statesman)