The jet set, baby, is nearly passe. Supersonic passenger planes don't quite exist yet. But the Boeing SST (supersonic transport) may be ready for paying passengers by 1975--for test pilots as early as 1971. The British-French Concorde, however, may take off before next year. This is the story of all of those airplanes that have never flown. The author travelled to the Concorde's factory hangar and to the nesting ground of the Russian Tu-144. But the bulk of the book--and it is a detailed account--concentrates on the story of America's SST. Still a somewhat mythic monster beset with problems both technical and political (i.e., convincing the public that SST travel is safe and comfortable), it will, when it materializes, fly nearly two thousand miles per hour. The author, a veteran aviation writer (American Grows Wings and Hollywood Pilot), knows how to make even technical data chatty. To his credit, he points out the book's main weakness: much of his material is tentative. Engineering, marketing, scheduling problems abound. The SST story will have to be told again. By 1975, it may well be a very different tale.