Longstanding rumor has suggested that producer Charles K. Feldman, having already bought the film rights to Mary McCarthy's novel in advance of publication, made sure it would be a best-seller by sending employees to bookstores all over America to buy up numerous copies of it. The prestige accruing to the book allowed him and Sidney Lumet to make the film with unknown actors and without too much interference.
As the most professionally established of the young actresses cast in the film, Shirley Knight was offered her choice between the two largest roles, those of Polly and Kay.