Cultural revolutions often happen so quickly that it's hard to pin down when they began, when they ended, and who blazed trails through the chaos. Throughout Gerald Nachman's show-business history Seriously Funny, legendary stand-up comedians and TV personalities grumble about the income they lost because contemporaries stole their acts and watered them down for mass consumption. But while it's true that Bob Newhart sat on a stool and talked into an imaginary phone a year or so after Shelley Berman did, and that Woody Allen became an icon by cobbling together Berman's neuroses, Jean Shepherd's curdled nostalgia, and Mort Sahl's intellectual incisiveness, it's also true that mockery and satire was free-floating as the Eisenhower years' public-relations mania gave way to the post-Kennedy era's acid cynicism. Anyway, as Seriously Funny makes clear, what really bugs comedy veterans is that they once had a few years as the beloved idols of hipsters and media types, and now they go largely unremembered, with no one to feed their adulation addiction. Most aging movie stars are like retired ballplayers, still charismatic and glowing; most aging comics are like retired boxers, frail and dead-eyed. Nachman's exhaustively researched book opens with nearly 50 pages of context-establishing introduction before giving way to 23 profiles of varying length, consisting of mini-biographies and extensive analysis of cult heroes like Tom Lehrer, Stan Freberg, Ernie Kovacs, Bob & Ray, and Lenny Bruce, as well as more broadly successful comics like Steve Allen, Nichols & May, Mel Brooks, and Bill Cosby, who sidestepped their colleagues' bitterness by switching to other creative outlets. Nachman doesn't dodge any of the personal failings of legends like Sahl, Sid Caesar, and Jonathan Winters, and he's openly critical of some of his subjects' acts, which he acknowledges were often more groundbreaking than amusing. But though Seriously Funny is fascinating throughout, each section gradually frustrates as Nachman abandons clear, chronological history in favor of wearying reiteration of each comedian's stylistic strengths and weaknesses, as attested to by everyone who ever met them. If Seriously Funny were organized less like a research resource and more like a broad overview and critical evaluation of its milieu, the book would be more edifying. As it is, readers have to slog through repetitive commentary to get to the hard facts of who these people were and what impact they had on the budding counterculture. The hard work pays off, though, in a richer understanding of both America's pop life and the ways comedy eventually obliterates its best.