A Private Listing at Candela-Designed 778 Park Avenue Yoo Jean Han/Sotheby's International The living room, with French moldings, includes a trio of floor-to-ceiling windows that open onto balconies. A beautifully proportioned apartment that commands nearly the entire 15th floor at the hyperexclusive 778 Park Avenue, an important pearl in the elegant prewar necklace of Upper East Side residences designed by Rosario Candela, is being offered for private sale by the family of its late owner, the ABC maestro Roone Arledge. The head of ABC Sports for 25 years, Mr. Arledge expanded his hands-on fief in 1977 to include the network's news division. "Wide World of Sports," "Nightline" and "20/20" were among his varied creations, as was Howard Cosell. The $29 million asking price includes the gracious 10-room simplex - distinguished by its French moldings, 11-foot ceilings, three marble fireplaces, three terraces and four exposures, the westerly one providing glimpses of Central Park - but not Mr. Arledge's imposing collection of Emmy Awards. He received his 37th and last, for lifetime achievement, in 2002, a few months before his death at age 71. Simultaneously intimate and grand, the apartment, No. 15, encompasses 4,500 -square feet and is reached by a private elevator landing that opens onto an impressive 30-foot-long gallery with its original wood herringbone-and-marquetry floor and mahogany doors with classic P. E. Guerin hardware. All of the principal rooms face Park Avenue and, like the rest of the residence, bear the neo-Classical imprimatur of David Easton, the decorator commissioned by the Arledges to refurbish the interior 16 years ago, before they moved in. They had looked at 35 apartments over two years before deciding on this one, seduced by its special address and fantastic light. There is one decorative carry-over from the apartment's previous owners, the horseman Albert C. Bostwick Jr., whose grandfather was a founder of Standard Oil and a partner of John D. Rockefeller, and his wife, Eleanor. In the dining room - where the recessed windows face north and east, the chandelier is vintage crystal and the fireplace is carved marble - the Arledges retained the hand-painted bird-and-floral chinoiserie wallpaper made by the historic firm Gracie, for its wow factor. Eleanor Bostwick, who had been widowed 14 years when she sold the apartment (after a bidding war) to Mr. Arledge in 1995, selected the wallpaper but agreed to leave it behind; doubtless she had ample incarnations of it at her 21-acre estate in Old Westbury, N.Y., where she died at age 100 in 2004. Then as now, it was a cash transaction. Among its many criteria for allowing transfers of ownership, the famously selective co-op board at 778 Park accepts only cash. Turndowns of even all-cash suitors are not unheard-of; Brooke Astor's much-photographed 16th-floor apartment, originally on the market for $46 million and ultimately bought by a hedge fund manager for $21 million in 2011, was at the mercy of the board through three years of price reductions and repeated offers from affluent buyers nonetheless deemed ineligible. The floor below the Arledge apartment is owned by William Lauder; other notable residents were William F. Buckley Jr. and his wife, Pat, whose home doubled as a literary salon. Also, back when the building was not resistant to hoopla, the actor Gary Cooper married the socialite/starlet Veronica Balfe at her apartment there in 1933. Besides the elegant dining room, the unit has a 28-by-21-foot living room with a trio of floor-to-ceiling windows that open onto Juliet balconies; an embrasure is sized for a sofa, and the marble fireplace is flanked by lithe caryatids. Mahogany doors connect the living room to the library, where the marble fireplace is in the Art Deco style; rumor has it Mr. Arledge was known to sneak onto the 15-foot terrace to enjoy the occasional cigar. There are three bedrooms, each with an en-suite bath. The master bedrooms can adjoin each other or be closed off; the main master has a 16-foot-long stone terrace facing Park Avenue; the other has two south-facing windows and a 7-by-12-foot terrace that offers a glimpse of Central Park across the rooftops. The third bedroom has partial park views, as do the maid's suite and the adjacent eat-in-kitchen. The brokers handling the sale are Serena Boardman and Meredyth Hull Smith of Sotheby's International Realty, the same team that used the "whisper listing" strategy to desired effect last year at a 730 Park Avenue penthouse ($39,000,018 after a bidding war) and at Theodore J. Forstmann's penthouse at 2 East 70th Street, which sold for $4 million above its $40 million asking price. To Ms. Smith, the "quiet" format makes sense for "offerings of this stature that are at the tiptop of the pyramid." She pointed out, "It's kind of like an I.P.O., and the amount of discretion it entails tends to be prized by potential buyers."