“M’ai,” according to director Anne Bogart, is a Japanese term for “the quality of space between two people.” M’ai is essential in martial arts–where a strong awareness of it can mean life or death–and in theater. Bogart investigated that concept over a period of two years while creating Cabin Pressure, her fascinating but sometimes flat-out irritating avant-garde play. While she was in residence at the Actors Theatre of Louisville, Bogart invited audiences into her rehearsals of Noel Coward’s Private Lives, then taped their responses to seeing the play in pieces and the actors’ reactions to being watched as they put the play together. She edited these transcripts and intercut them with a text that also included excerpts from Private Lives and Albee’s Who’s Afraid of Virginia Woolf?–scenes involving characters performing for others in social settings–then liberally sprinkled in quotations about theater and audiences from prominent playwrights, performers, and directors: Robert Wilson, Joseph Chaikin, David Mamet. The resulting piece for a cast of five, premiered earlier this year at the 1999 Humana Festival, is more lecture than performance, more essay than finished work of theater. Still, it contains some fascinating meditations on the relationship between audience and performer: the audience members’ often bizarre, self-absorbed comments about the performers are a revelation. And as in her earlier foray into nonfiction drama, Bob–about Robert Wilson–Bogart leavens her investigations with plenty of humor and wit. Ruth Page Theater, 1016 N. Dearborn, Chicago, 773-722-5463. Opens Thursday, December 9, 8 PM. Through December 12: Friday-Saturday, 8 PM; Sunday, 3 PM. $22. –Jack Helbig