James Wolcott’s career as a critic has been unmatched, from his early Seventies dispatches for The Village Voice to the literary coverage made him equally feared and famous to his must-read reports on the cultural weather for Vanity Fair. Bringing together his best work from across the decades, this collection shows Wolcott as connoisseur, intrepid reporter, memoirist, and necessary naysayer.         We begin with “O.K. Corral Revisited,” Wolcott’s career-launching account of the famed Norman Mailer–Gore Vidal dust-off on the original Dick Cavett Show. He goes on to consider (or reconsider) the towering figures of our culture, among them Lena Dunham Patti Smith, Johnny Carson, Woody Allen, and John Cheever. And we witness his legendary takedowns, which have entered into the literary lore of our time. In an age where a great deal of back scratching and softball pitching pass for criticism, Critical Mass offers a bracing taste of the real thing.