This biography of a White House enfant terriblea dashing beauty in a broad-brimmed hat, witty and eccentric enough to dominate Washington society for decadesis also a gossipy chronicle of the American establishment families whose whims have often shaped modern history. President Teddy Roosevelt s eldest, Longworth (1884-1980) was born to privilege and made the most of it. During a lifetime of travels, teas and dinner parties, she pulled social pranks and cast cruel barbs at those who failed her expectations, such as her husband, popular House Speaker Nicholas Longworth, and her reticent daughter Pauline (whose father, the author hints, was Idaho Sen. William Borah). She also despised cousins Eleanor and FDR, but nevertheless demolished his 1944 election opponent, Tom Dewey, as "the little man on the wedding cake." Syndicated book columnist Felsenthal aptly captures period flavor in a narrative well stocked with anecdotes and conversations between the vibrant Longworth and a circle of acquaintances that included the dowager empress of China, Warren G. Harding, Nixon, Joseph McCarthy, Jack and Bobby Kennedy, Castro and Ezra Pound. At age 96, "too frail to support her hats," the darling of public, press and many ambitious politicians died in a decaying Washington mansion once bright with celebrity. Although the biography is lively and interesting, Felsenthal does not probe behind the legend, leaving the reader to wonder whether being a "fascinating conversationalist" merits such lasting notoriety. Photos. BOMC alternate.