Pulitzer Prize winning David Mamet has slipped into Hollywood directing and writing both studio and independent films

Interior: a movie set inside the rich, high-ceilinged rooms of a South London Edwardian mansion in a state of genteel decay, springtime. — Muttering lines under their breath, the pensive actors in big hats and morning coats arrange themselves in their assigned spots around a grand staircase. — The air is one of studious concentration. All is quiet. The camera rolls.

Director: Lovely. That’s just great, thanks. (He turns to one actor.) Speak it out a little bit more definitely, but that’s good. Let’s try it again, shall we?

Cut. Can that director really be David Mamet, leaning against a wall in his tweed cap and black jeans, playing his role so gently? The working environment Mamet has created here on the set of The Winslow Boy, his adaptation of the 1946 Terence Rattigan play, may have the same shape and momentum as one of his plays — fast and lean and elegant as a race hound, not a word wasted or out of place — but the intonations are startlingly different. Typical Mamet characters spit out four-letter words like bullets (see Glengarry Glen Ross), but today there’s no profanity; only some laughter, some courteous and extremely quiet consultation, and more pleases and thank-yous than a child’s etiquette lesson.

Mamet can afford to be polite. At age 50, the Pulitzer Prize-winning playwright has found a unique, prestigious, and profitable niche in Hollywood, sliding effortlessly between writing popular studio movies (The Untouchables, The Edge, and last winter’s biting political satire Wag the Dog, which he cowrote) and directing his own more cerebral independent films (like 1994’s Oleanna, which he adapted from his own scathing play about sexual harassment). This spring, Mamet has scored his first unqualified indie hit — The Spanish Prisoner, starring Rebecca Pidgeon (Mamet’s wife, who also stars in The Winslow Boy) as the is-she-or-isn’t-she femme fatale and Steve Martin as a shady mogul who lures Campbell Scott into a web of intrigue.

Even as more and more art-house offerings are languishing on the remainder shelf, Spanish Prisoner, Mamet’s fifth directorial effort, is shaping up to become Sony Pictures Classics’ highest-grossing movie ($5.9 million, so far) since John Sayles’ Lone Star. It also celebrates one of Mamet’s favorite themes — the confidence game. ”All of us have stories that draw us back again and again,” he says. ”Spielberg makes movies about the clash of alien cultures — extraterrestrials and earthlings, or the Africans and the Americans, or the Jews and the Nazis. Martin Scorsese likes stories about Italian Americans and the Dalai Lama. I like telling stories about confidence games.”

Despite his success, though, Mamet has no plans to give up what he calls ”this avocation of writing [studio] movies once in a while for hire.” According to Spanish Prisoner coproducer Sarah Green (who is producing The Winslow Boy with Sayles’ girlfriend/partner, Maggie Renzi), Mamet takes on the larger projects so he can afford to demand absolute creative control over the smaller films that he directs himself, which are much closer to his heart. They’re also usually a difficult sell to mass audiences. ”His stuff is unusual and doesn’t pander,” Green says.