Many men of a certain age - and disposition - remember when you could see raw sex on a movie screen only at what were called "smokers," private showings in which film reels hummed and tobacco smoke rose into the beam of light.

That was before the '70s, and before Marilyn Chambers and a film called "Behind the Green Door."

Chambers was found dead Sunday in her home in Santa Clarita, Calif. She was 56. The cause of death had not been determined.

"Behind the Green Door" was among the first hardcore pornographic films widely released in the U.S., and it caused a sensation. The subsequent porn-movie industry, in which you can go to a regular movie theater - with or without raincoat - and watch XXX films in approximate comfort, traces its legacy to pioneers like "Green Door."

It helped launch what some wags refer to as the "Golden Age of Porn," and "porn chic."

"Behind the Green Door" was notorious for a couple of reasons. First of all, when the film was released, boxes of Ivory Snow showed Chambers, in a straight modeling job, cuddling a baby and looking for all the world like Procter & Gamble's slogan, "99 and 44/100% Pure."

Ivory Snow sales skyrocketed, but the company quickly substituted another model for the no-longer-pure Chambers.

The film was also scandalous because it featured a sex scene between Marilyn and a black actor, Johnny Keyes. That just wasn't done in the Hollywood of the time.

Made on a budget of $60,000, the movie ultimately grossed more than $25 million, including its video release.

Chambers, who grew up as Marilyn Ann Taylor in a middle-class home in Providence, R.I., went on to star in many other porn films, as well as other movies not considered Academy Award quality.

In one, titled "Rabid," she played a woman who feeds on human blood from an orifice in her armpit, spreading an incurable disease.

She continued to do porn into her middle years, working for such companies as Naughty America and MILF Hunter.

In an interview with Daily News columnist Dan Gross in 2003, she said that she was studying nursing and working with seniors, who she said didn't recognize her.

About "Green Door," she told Dan, "The media attention of the whole controversy was insane. This was the first time attention was being paid to erotic films. It's very historical."

Marilyn also had a singing and political career of sorts. In 1977, she released a disco single, "Benihana," on Roulette Records. It made the R&B charts and Hot 100.

She was on the ballot in Utah as the Personal Choice Party's candidate for vice president in the 2004 election. She got 946 votes. Last year, she was a write-in candidate in nine states as the Boston Tea Party's candidate for president.

In her teens, Chambers left home - and her parents, who didn't speak with her for two years after "Green Door" came out - and went to the West Coast for a modeling and acting career.

She was portrayed by actress Tracy Hutson in a Showtime film, "Rated X," in 2000.

Chambers was married and divorced three times. She had a daughter, McKenna Marie Taylor, with her third husband, Tom Taylor. *