"I can tell a Chicago actor from a New York actor in 10 minutes," says William L. Peterson, who is a Chicago actor, and a highly regarded one at that.

"We're right in the center of America, a city of broad shoulders, and fortunately we don't have a history of pretension. Chicago has a blue-collar theater. If you spit or drool on your face while you're performing, you leave it there until it dries."

Peterson does considerably more in "In the Belly of the Beast: Letters From Prison," one of four plays that the Kennedy Center is importing from the Windy City this summer. Fashioned from the fierce prison writings of Jack Henry Abbott , the convicted murderer whose literary skills were momentarily championed by novelist Norman Mailer, "Belly" opens Friday night as the inaugural production in the Center's Free Theater.

The production has already received excellent notices in Chicago, Glasgow and most recently London, and Peterson has come in for a large share of the praise with a performance that goes right to the gut. The 32-year-old actor says he was "blown away by the material" when he was first approached in 1983 by the Wisdom Bridge Theatre to play Abbott. "I realized that if I accepted the role, I would find out once and for all if I was an actor. Abbott is so naked to me and the role seemed so personal. Performing it has shown me my weaknesses -- what I have inside me that is sad, dangerous, paranoid, afraid. And I think it's also put me more in touch with the elements that make our lives better -- love, growth, sharing, intimacy, all those things that Jack doesn't have."

Peterson has never met Abbott and is not sure he wants to. "Sometimes I feel I'm ripping him off. I mean, he's in solitary confinement in Marion, and I'm on a stage in London!"

Clearly on a roll, Peterson recently completed filming "To Live and Die in L.A.," William Friedkin's latest film, in which he plays a Secret Service agent chasing down the counterfeiter who killed his partner. But while the show business portals seem to be swinging open for him, he's not ready to jump Chicago yet. "I guess I'm a midwest guy. When I go to Los Angeles or New York, I can't stand that pressure to succeed. Actors in New York or Los Angeles do shows in order to get other shows. In Chicago, we do the work."