There's something great and disturbing at work in Auto Focus, Paul Schrader's new bio-pic of the life and death of notorious ex-TV star turned porn junkie Bob Crane. The film begins as a colorful trip through the gauche late sixties and ends as a dark and sad story in the late 1970s. And along the way, the film's sunny initial optimism and innocuously naughty escapades give way to a rising undercurrent of sexual doom and loss that take on the proportions of a great tragedy.

By now everyone is familiar with the short-lived and minor career success of Bob Crane, the star of "Hogan's Heroes." But Bob Crane will never be remembered for any artistic contribution in the entertainment industry. With great economy and careful attention paid to period detail, Auto Focus essentially is the story of Crane's rise up through the ranks of radio broadcasting, television success and his fall down through a spiral of sexual addiction; that cost him two marriages, a career and ultimately his own life.

When we first meet Crane, he's a jovial and seemingly happily married man. God-fearing and devoted to his wife and kids, he's a family guy for all intents and purposes. But soon after landing a starring role on television, Crane's weakness for women and sex is exploited by the motives of a questionable new friend, John Carpenter (an incendiary Willem Dafoe) or "Carpy," as he's affectionately called. Carpy, it turns out, is a sales rep for a new technology called the "VTR," or video tape recorder, and once he and Crane begin dabbling in this fascinating new technology and give in to their darker, sexual vices, the lethal combination blows the lid off Crane's professional and personal world, setting in motion years of lies, cheap orgies, pornography and sex addiction.

By the time Auto Focus hits full throttle in its second and better half, Crane has turned into a full-fledged sex maniac, and his escalating addiction to all things erotic and its subsequent effect on his career are captured in vivid detail, not the least of which come from Kinnear's fine performance.

As the film opened, I wasn't convinced he was Crane - they certainly don't look that much alike, and his line readings were mannered almost to a fault. But then Kinnear hits his stride after the break-up of Crane's first marriage and his gradual descent into a personal darkness. Kinnear is finally fascinating as a has-been celebrity using his faded star to get sex, resistant to the warnings of his agent about his increasing separation between his personal life and public persona.

Auto Focus is no easy portrait of a struggling addict who comes clean and turns his life around. Even when his world is crumbling around him, and everyone else can see it (except Carpy, of course) Crane defiantly refers to himself as nothing more than a "red-blooded American man," living a mantra of "a day without sex is a day wasted."

If Crane continues to insist that he's "normal" throughout the entire film, his best buddy and predatory mentor Carpy is never anything more than an amoral creep with charisma. These two are one of those incredible, mis-matched pairs that alone are probably harmless, but together create a synergy out of which emerges something awful. Schrader dares to go right to the edge with Auto Focus, and its scenes of group masturbation, orgies and straightforward attitude to Crane's obsessive approach to the next encounter is sobering.

Auto Focus, as directed by Paul Schrader with a fine sense of the erotic macabre and not a trace of sentimentality for its subject, is a tough film with a single-minded, unrepentant subject. It's a rich character study, and avoids the usual politically correct trappings of Hollywood cinema. As a portrait of a celebrity gone wrong and undone by unsavory and unchecked impulses, it's a vital and fascinating film.