One of the best-known openly gay couples of the 20th century, Christopher Isherwood and Don Bachardy have been well-chronicled. Yet there's a richness and emotional impact to the documentary "Chris & Don: A Love Story" that should give even their most obsessive followers rewarding new insights.

Made over a number of years by the directing team of Guido Santi and Tina Mascara, the film benefits from a wealth of home movies, Isherwood's literary legacy and, most powerfully, extensive interviews with Bachardy and access to his work and life. The artist's honesty about the 33 years he spent with the writer makes this an unusually deep and persuasive cinematic examination of love. It's hardly a warts-and-all expose, but by acknowledging its imperfections, the film renders this relationship as all the more exceptionally nurturing.

For those not in the know, Isherwood was the upper- class English author whose short-story collection, "Goodbye to Berlin," was eventually adapted into the hit musical and film "Cabaret." Before World War II broke out, Isherwood relocated to L.A. and became a mainstay of the Hollywood and emigre artist social scene.

In 1953, the 49-year-old author met 18-year-old local Bachardy on the beach. In short order, they moved into a bungalow in Santa Monica Canyon, where the couple remained until Isherwood's death in 1986 and Bachardy remains today.

Though they knew (and, sometimes, had affairs with) many closeted gays, Isherwood and Bachardy never hid their homosexuality in an era when that wasn't acceptable - and they felt great about it. The relationship had other tensions, though. Infidelity, as already mentioned. And their vast age difference, which didn't bother them so much as it did some of their otherwise open-minded friends. Don's big problem, for a long time, was that Chris was so accomplished, the younger man felt unformed and directionless by comparison; the way some of Isherwood's highfalutin pals dismissively treated Bachardy reinforced that notion.

But Isherwood, who couldn't help but view his lover like a son as well, remedied that by encouraging Don to draw. Bachardy painted many of their famous friends, and his work is now part of permanent collections at the Smithsonian, UCLA and other prestigious institutions. But Chris was his first subject and, during the years he was succumbing to cancer, Bachardy sketched him every day. These drawings make for a devastating formal coup in a film that has numerous delightful visual flourishes.

Nowadays, you might see the elderly, incredibly fit Bachardy bicycling around the beach or Beverly Hills (his driver's license was revoked some years ago and he saw no reason to get it renewed). He proudly acknowledges that he's his mentor's creation. But what "Chris & Don" shows is that nothing makes an individual as whole as finding one's true love, and sticking with them through the whole winding journey of life.

CHRIS & DON: A LOVE STORY

Not rated: nudity, sex, drug use, language.

Director: Guido Santi and Tina Mascara.

Running time: 1 hr. 30 min.

Playing: Nuart, West L.A.

In a nutshell: Deeply moving documentary about the 34-year romance between writer Christopher Isherwood and the much-younger artist Don Bachardy.