Along the way, Playboy developed a journalistic form that has become a virtual trademark, in the same way that The New Yorker put its own stamp on the personality profile. The magazine's editors routinely call it the interview of record, and, to celebrate the form, they have published an anthology, "The Playboy Interview: The Best of Three Decades."

Interview subjects must sign on for the long haul. The magazine relies, for the most part, on a stable of seven or eight writers who research their subjects extensively and extract from them a commitment to sit for extended interviews, usually no less than 6 hours, sometimes as long as 40. The interviews are usually conducted in several sessions, sometimes over a period as long as six months. The magazine rarely imposes deadlines. 'When It Gets Interesting'

Larry DuBois spent two years interviewing Robert Redford in fits and starts before completing his assignment. Not long after the murder of Sharon Tate by Charles Manson and his followers in 1969, the magazine paid for him to spend six weeks in London and St.-Tropez with her widower, Roman Polanski, to establish rapport before actually beginning the interview.

Murray Fisher, who edited the interviews from their inception until leaving the magazine in 1974, described the process as equal parts psychoanalysis and jury trial, with the interviewer reserving the right to cross-examine.

"Celebrities are used to being interviewed," he said. "They have a ready-made set of answers to questions they've been asked before. So you ask those, but then you don't leave. You let them exhaust their repertory of defense mechanisms, and after three or four hours you're down to bedrock. That's when it gets interesting."