SFIFF Robert Towne has accomplished something rare: in an industry that paradoxically singles out the director of a movie as if he or she were the sole creator of what is actually a collaborative effort, he has tasted fame, received recognition, and secured his place in the history of cinema for writing scripts.

Having started his career penning B-movies like Last Woman on Earth (1960) and The Tomb of Ligeia (1964), and working as a script doctor for impressive projects such as Bonnie and Clyde (1967), Drive, He Said (1971), and The Godfather (1972), Towne truly rose to stardom with Chinatown (1974). This dark, pessimistic tale about power struggles and government corruption in Los Angeles, which garnered Towne an Academy Award for Best Original Screenplay, not only stands up to such noir classics as The Maltese Falcon (1941) and The Big Sleep (1946), but also redefines the whole genre. In J.J. Gittes — as embodied by Jack Nicholson — Towne introduces his own version of a Phillip Marlowe character, tough but hopeless, into a world where crime is hard to detect and impossible to punish, even when committed in broad daylight.

Shampoo (1975) features a Towne screenplay that's as complex and intriguing as the one he wrote for Chinatown. Yet it takes a secondary role on Towne's résumé, despite the fact that it yielded an Academy Award nomination. Perhaps this is because Warren Beatty shares Shampoo's writing credit with Towne, whereas Chinatown was presented as solely Towne's creation. (Of course, it's an open secret today that Towne wrote a different, happy, ending for Chinatown, which director Roman Polanski replaced — fortunately — with a devastating one.) In any case, it's a pleasant and unexpected surprise that the San Francisco Film Society has chosen to showcase Shampoo while presenting Towne with this year's Kanbar Award for excellence in screenwriting.

As the critic and teacher Elaine Lennon points out in a 2005 piece for Senses of Cinema, the true complexity of Shampoo's script stems from the same element the film has been derided for — its superficially silly comic spirit. Lennon suggests that the many influences detectable in Shampoo include ancient Greek tragedy, the restoration comedies of 17th- and early 18th-century England, and the plays of Molière. All of the above construct poignant social critiques while providing comic relief.

Indeed, Shampoo uses the sexuality that permeates its turbulent and intricately woven Beverly Hills microcosm to farcically comment on the United States of the late 1960s. George (Beatty), the restless hairdresser with a soft spot for his customers, his girlfriend Jill (Goldie Hawn), his ex-girlfriend and lover Jackie (Julie Christie), his other lover Felicia (Lee Grant), and Felicia's husband and Jackie's sugar daddy Lester (Jack Warden) not only share the same lovers, they share the same anxiety — a feeling produced by an ever-changing, unstable society. To put it differently, their sexual misbehavior is a manifestation of the fluidity and uncertainty of their lives.

In comparing Shampoo to Chinatown, ...