Another merry riff on Washington power politics, struggles, and failures from the venerable curmudgeon and sage: an appealingly unholy marriage of Burr, Duluth, and a suavely Vidalian amalgam of Tom Sawyer and Tom Swift. In 1939, a 13-year-old prep school student who's identified only as ""T."" (and who, we soon learn, is a ""teenage mathematical genius"") is yanked out of classes and driven to the title location's main building (""the Castle""), where, after meeting wax figures who come mischievously to life after the doors are closed to the public, he becomes a pivotal figure in crisscrossing plans to either avert or win a forthcoming world war. Specifically, undisclosed forces (among them may be James Smithson, the Institution's presiding genius) have determined that T., also, incidentally, ""the best schoolboy pitcher in the Washington, D.C., area,"" may possess knowledge that will enable his country to detonate a nuclear bomb without producing the ensuing chain reaction certain to destroy the world. After a disturbing first few hours within the Castle, during which he's declared ""prime veal"" and almost parboiled in the Early Indian Exhibit Room (then relieved--to his relief--of his virginity by a non-Native American ""Squaw""). T. settles sturdily down to business, reassuring a depressed-looking Abraham Lincoln and a truculently pacifist Charles Lindbergh, explaining to Robert Oppenheimer just where Einstein went wrong, and, thanks to a jury-rigged thermostat, traveling about in ""innumerable parallel pasts."" Only a cad would give away the beguiling results of T.'s refreshingly ingenuous adventures and discoveries--not to mention the dozens of ingenious anachronistic gags with which the narrative is studded. This may be the wisest book that Vidal--this incomparably urbane observer of our revered past, debased present, and unpromising future--has even written. It is, as well, entertainment of the highest order. Even Norman Mailer will like this novel.