The boozy stage memoir of a career on Broadway is turning into a genre of its own, now that a great generation of Broadway babies is growing old. Charles Nelson Reilly came to town two years ago with a chatty, gossipy monologue that proved to be a huge amount of fun; he rattled off stories about acting classes with Uta Hagen, friendship with Jack Lemmon, and early productions of Hello, Dolly! Now Elaine Stritch is at it with a higher-profile show in which she not only gossips and confesses but also sings, magnificently. "The Ladies Who Lunch," "I'm Still Here," "Why Do the Wrong People Travel?," "Broadway Baby," and a dozen other warhorse tunes are threaded into a funny but melancholy Bildungsroman of success and failure during the great age of New York theater -- when Marlon Brando, Tennessee Williams, and Stephen Sondheim were young. She dated Brando. She partied with Noël Coward. She understudied for Ethel Merman, and claims to have watched her -- Merman herself -- toss a drunk heckler out of the theater midperformance. She fell in love with Rock Hudson in Rome. She also drank, and the drink becomes so hard to ignore that Stritch's battle with it dominates the dark, intimate second act. At Liberty is not just an insider's history of the American musical; it's also a moving personal document, a drama that just happens to be studded with old familiar tunes performed in the old style, from an age before World Wrestling had a marquee on Times Square.