Mart Crowley, whose 1968 play, “The Boys in the Band,” put gay characters and their stories front and center in a way that had rarely been seen in a mainstream New York theater, died on Saturday night in Manhattan. He was 84.

His friend the actress Natasha Gregson Wagner said the cause was complications of heart surgery.

Where previous plays and movies often tiptoed around a character’s homosexuality or, worse, demonized gay characters, Mr. Crowley’s play presented gay men talking forthrightly and in depth about their lives. It featured nine men at a birthday party in which alcohol flowed and conversation grew brutally honest as a result.

“The power of the play,” Clive Barnes wrote in his review in The New York Times, “is the way in which it remorselessly peels away the pretensions of its characters and reveals a pessimism so uncompromising in its honesty that it becomes in itself an affirmation of life.”