In 1953, ""Piltdown Man""--the 1912 discovery, in Sussex, of Early Man skull fragments--was revealed to have been a fake. But it could never be determined what roles were played in this hoax by the three Piltdown pioneers: amateur paleontologist Charles Dawson, British Museum curator Arthur Woodward, and young French Jesuit scientist Pierre Teilhard de Chardin. Here, then, Marks (Hang-Ups, Collector's Choice) offers a speculative fictional version of who-done-what and why--in a stylish, sly entertainment that's marred by excesses (both lurid and silly) in the sex-secrets and sneaky motives behind the Piltdown scheming. According to Marks, the hoax mastermind was lawyer/fossil-hunter Dawson, a big, blustery sort whose ambition was fueled by his adulterous lust for a local matron. Dawson, it seems, forced prissy Woodward to join in the conspiracy via nasty blackmail: secret evidence (obtained from the notorious Edmund Backhouse, Trevor-Roper's Hermit of Peking) of Woodward's predilection for homosexual sado-masochism. And soulful yet shrewd Teilhard--yearning for lofty scientific achievement, straining to transcend Churchly limitations--was Dawson's dupe. But who, then, was it who salted the Piltdown dig with a purposely clumsy forgery? And what was the true cause of Dawson's untimely death (from blood poisoning) in 1916? Marks goes over the edge from clever whimsy to contrived foolishness in some of this unraveling--especially when Arthur Conan Doyle is dragged in (along with his well-known belief in Spiritualism). The sexual kinkiness, too, is graphically overdone. But aficionados of playful, ironic historical reconstruction may want to dig through to the end nonetheless--thanks to Marks' seductive narration (flashbacks within flashbacks), his sturdy gift for offbeat character, portraits, and his deft handling of period touches (like the tea-cloth being needlepointed by Woodward's monstrous wife) and scientific details.