EASY RIDERS, RAGING BULLS How the Sex-Drugs-and-Rock 'n' Roll Generation Saved Hollywood By Peter Biskind Simon and Schuster. 506 pp. $25

Peter Biskind's devourable book is that rarity, a Hollywood expose that you can read -- mouth agape, slurping up scandal and titillation so fast you're in danger of choking -- without feeling ashamed of yourself. Unlike, say, Kenneth Anger's "Hollywood Babylon," which appealed to no interest beyond the prurient, "Easy Riders, Raging Bulls" has a thesis, which goes something like this: The wave of screenwriters and directors that washed into Hollywood in the late 1960s and dominated the industry through much of the '70s -- turning out such fresh, intelligent and entertaining movies as "The Graduate," "Bonnie and Clyde," "The Last Picture Show," "The French Connection," "M*A*S*H," "Nashville," "The Last Detail," "The Godfather," "American Graffiti," "Mean Streets" and "Chinatown" -- went on to squander its gifts in a binge of drug addiction, megalomania and hypertrophic flops.

Some of the details cited by Biskind, a veteran movie journalist, may be familiar -- the on-location hell of Francis Ford Coppola's "Apocalypse Now," for example, or the gargantuan cost overruns incurred by Michael Cimino in filming "Heaven's Gate," a box office disaster that has become a byword for American auteurist excess. But there is an enormous amount of new material here, and the book's value lies in its comprehensive picture of hubris and Schadenfreude, of adulation and addiction, of talented men absolutely corrupted by absolute freedom.

What vested so much control in young film school grads and sound stage schmoozers was panic among the moguls. "By the late '60s," Biskind writes, "the studios were in dire financial shape. According to Variety, 1969 marked the beginning of a three-year slump. Attendances, which hit an all-time high of 78.2 million a week in 1946, plunged to a low of 15.8 million a week in 1971." With aging studio bosses and producers drained of confidence in their own taste, almost any young director with a hit (and several without one) could, in the words of writer-director Paul Schrader, "just waltz in and have these meetings and propose whatever. There was nothing that was too outrageous."

Some of the newcomers simply lucked out. As Biskind tells it, film critic Peter Bogdanovich "went to a screening . . . in Hollywood. {Maverick director} Roger Corman was sitting behind him. Someone made introductions. Corman knew his byline from Esquire, asked him if he would be interested in writing for the movies. Bogdanovich was, and Corman hired him as his assistant director on The Wild Angels.' "

Bogdanovich recalled, " I went from getting the laundry to directing the picture in three weeks.' " A few years later Bogdanovich made "The Last Picture Show," and was the toast of Hollywood. (A few more years, and he was just toast.)

Others, like Schrader (who before his decline directed the esteemed "Blue Collar" and the boffo "American Gigolo"), schemed their way into power. "What kind of a relationship can you have with someone," a well-connected young actress wondered, "when you {expletive} them, and then you turn over, and they're asking you to give a script to Clint Eastwood? . . . I really think {Schrader} would steal his own mother's diary if he could." The book is so crammed with memorable vignettes that I wore down my pencil marking them. Here are some examples, logged while the point was still sharp: Coppola, having failed to persuade such big names as Steve McQueen to work for him in "Apocalypse Now," threw "his five Oscars out the window, until all but one lay on the sidewalk, shattered." Screenwriter Jacob Brackman becoming so fond of nitrous oxide that, on the strength of a doctor's prescription, he buys a tank to hold the gas, orders periodic refills from a supplier and deducts the costs as medical expenses. Director Roman Polanski, on hearing that producer Robert Evans has been arrested for possessing 35 pounds of cocaine: "What was he trying to do, make a line from New York to Paris?" Coppola again, in one of his manic phases, proposing to make "a ten-hour film version of Goethe's Elective Affinities' in 3-D." Schrader trying (but ultimately failing) to love men because gay parties in the late '70s are so "cutting edge."

One thing troubled me about the book: For long stretches it reads like a brief for the prosecution. With rare exceptions (the hoggish Coppola, for one, is shown committing occasional acts of generosity and artistic integrity), the directors and producers who get Biskind's attention are so colossally loathsome, so flawlessly egotistical, that you begin to wonder if he doesn't have a weird interest in the worst and the foulest. Yet he seems to have functioned as a kind of father-confessor to his subjects, and the very airing of all this dreck -- the willingness of so many Hollywood insiders to spill so many shabby stories about each other -- stands as a perverse testimonial to the accuracy of his group portrait. The sourcing, by the way, is scrupulous, and where a player denies a scurrilous tale about him- or herself, Biskind notes same.

So where are the wonder boys of yesteryear? One, Hal Ashby, is dead, and several, such as Bogdanovich and William Friedkin, are notable for their absence from the screen. George Lucas has apparently resigned himself to spending the rest of his career rounding out the puerile "Star Wars" saga; the latest movies from Robert Altman and Coppola -- in each case a chip off the John Grisham block -- can hardly be considered personal statements; and Steven Spielberg often seems out of his depth when he makes films for grown-ups. Of all the no-longer-young Turks, perhaps only Martin Scorsese has lived up to his early promise.

I finished "Easy Riders, Raging Bulls" with renewed nostalgia for the studio era, with its cinematic checks and balances. As Howard Hawks, an old non-raging bull, pointed out to one of Biskind's sources, "The studio system worked because we couldn't be excessive, we couldn't just do what we wanted to do." More than that, in the '30s and '40s the studios were chockablock with people who loved what they were doing, a passion reflected in the period's relatively high proportion of trim, well-crafted movies. To oversimplify only slightly, the excesses committed by the cinematic '60s generation paved the way for the comeback of the producer -- and a different kind of producer at that: "a new breed of hustler," in Biskind's words, "who just smelled money." What we are left with, after the failure of the Easy Riders' "revolution," is a Hollywood in which the average movie is pegged to the mind of a 12-year-old boy. The whole, sad story is here, masterfully told by Peter Biskind. Dennis Drabelle's articles on the movies have appeared in the Atlantic Monthly, Film Comment and Civilization magazines. CAPTION: Peter Biskind explores the excesses of '60s and '70s auteurs in "Easy Riders."