It's an old story in literature, but not so common in rock criticism because rock criticism isn't old enough to have developed a well-documented history or insightful biographies about its practitioners.

But to the extent it has an important past at all, it's because of Lester Bangs. An often-great writer, he lived a very tough life. (Philip Seymour Hoffman reportedly is scheduled to play him in an upcoming movie.)

Starting in the late '60s with Rolling Stone magazine and continuing through the '70s with Creem and Village Voice, especially, he made the writing of rock frequently more interesting than the music.

Influenced by the Beats, his writing could be jet-propelled and phantasmagoric, yet also lucid and passionately confessional. And his observations could be brilliant, if sometimes obsessively rantlike. Bangs died at age 33 in 1982 from an overdose of Darvon.

In 'Let It Blurt: The Life & Times of Lester Bangs, America's Greatest Rock Critic,' Jim DeRogatis tries to make sense of Bangs' legacy. A rock critic for the Chicago Sun-Times, DeRogatis understands his subject's importance. And he does a satisfyingly effective job of explaining it to those who know less about rock than he does.

Bangs championed and helped create the world of 'alternative rock' - alternative to commercial success, often. His taste has guided the development of rock aesthetics; one of his first reviews was a rave of the difficult Captain Beefheart. He admired the Detroit noise bands and the New York punks.

His obsession with the ups and downs of Lou Reed's career seemed almost stalkerlike. DeRogatis shows how their interviews turned into heated, insulting arguments that Bangs dutifully reported to readers.

Perhaps Bangs' finest and funniest essay was 'Psychotic Reactions and Carburetor Dung,' which imagined the masterpieces that one-hot-wonder one-hit- wonder Count Five turned out after 'Psychotic Reaction.' Bangs' story had many readers searching record bins for the non-existent Count Five albums he had praised. It spurred interest in 1960s-era garage rock, an interest that has never ceased.

But Bangs' life was sordid and lonely. He was an alcoholic and drug abuser who could fall asleep on a New York street corner like an unwashed bum, which is what he often resembled. He moved through girlfriends like unwanted record albums, desperately falling in love with each but then proving too exasperating or unfaithful for mates to tolerate.

Few who read this book will want to emulate Bangs. Like many of the grungy musicians he championed, he had little money to show for his hard work and influence. But he did have access to the record-company promotional apparatus that supplied free parties and junkets for writers. At one in Memphis, DeRogatis recounts, Bangs got drunk and then urinated on the driveway at Graceland - because Elvis wouldn't come meet him.

There are many more stories like that in 'Let It Blurt,' as well as Bangs' desperate love for Romilar cough syrup. As DeRogatis reports, Bangs said that Romilar turned him into a 'creep who couldn't do anything but stumble up to people and bellow HAW! HAW! HAW! in their faces like a wacked-out aborigine.' Bangs liked that feeling.

The book, for which DeRogatis did thorough research and extensive interviews, includes plenty of Bangs' substance-abusing antics. But it also offers insights into his ideas about rock and pop culture, and details about how some of his more notable stories came about.

DeRogatis' best contribution is in bringing to light Bangs' troubled yet oddly liberating childhood in Southern California. His father died in a fire when Bangs was a child, and his mother was a Jehovah's Witness who frowned on popular entertainment. But he was deeply creative, and his hardships made him wilder. When he cut gym class and his instructor demanded he write a makeup assignment, Bangs responded with 'Hector the Homosexual Monkey' - and was suspended for another week.

He was like that, defiant toward discipline and authority. That attitude helped make his life a mess, but it made his writing strong. 'Absent Lester's ideas, the poetry of his writing, and his singular lust for life, this story would not have been worth telling,' DeRogatis writes in 'Let It Blurt's' preface. 'Those are the parts of his legacy that I celebrate.'

(Steven Rosen's e-mail address is srosenone@aol.com.)