When "The Glass Menagerie" opened on Broadway in March 1945, the actress cast as Southern matriarch Amanda Wingfield got so drunk before the show that a bucket was placed in the wings so she could throw up between scenes.

Seated six rows from the stage was the 34-year-old playwright, Tennessee Williams, who was struck by Laurette Taylor's "supernatural quality on stage." When the final curtain came down, the cast took 24 curtain calls to thunderous applause, and Williams, wearing a gray flannel suit with a missing button, mounted the stage to repeated cries of "author, author."

John Lahr, the former chief theater critic for The New Yorker, begins his definitive new biography of the great American playwright with this vivid anecdote, then manages (for the most part) to sustain the momentum for the next 600 pages.

The culmination of 12 years of work, "Tennessee Williams: Mad Pilgrimage of the Flesh" is a dazzling, deeply sympathetic and psychologically acute look at the life and work of a tortured genius who rocketed to fame after World War II with a new kind of play that reflected his "haunted interior": dreamy and poetic, passionate and tender, sensual and spiritual, desperate for recognition and more than slightly tinged by the family madness. "On stage and off it," Lahr writes, "hysteria was Williams's idiom."

Beginning with the opening night of "Menagerie," Lahr moves back and forth in time to chart Williams' sensational rise and agonizingly long and humiliating decline, exacerbated by pills and booze, beginning around 1961, when he had his last hit on Broadway, "The Night of the Iguana."

We meet the leading men with whom he conducted tempestuous and ultimately unhappy love affairs; Elia Kazan, his most important collaborator; and an A-list of actors who starred in his dramas, including Marlon Brando, who read for the Stanley Kowalski part in "A Streetcar Named Desire" when he was just 23.

Lahr's writing can, at times, be disorienting, and certain passages seem overly long. His technique is to layer together quotations and reflections from Williams' circle of intimates, sometimes making it hard to figure out who's saying what.

But these are minor quibbles in an epic achievement that will be relevant not just to theater buffs but to anyone interested in the "spiritual shift" that occurred in American life after the war and that Williams, for a time, so brilliantly captured with his unique brand of "personal lyricism."