Author Steven Watts has penned an explosive new book about Playboy founder Hugh Hefner to hit shelves in October. A younger Hugh starred in his own adult movie, engaged in trysts with other men, and even had sex with his sister-in-law, according to Watts’ tawdry new tell-all, Mr. Playboy: Hugh Hefner and the American Dream.

One excerpt reads:

“(A foursome) did happen with his brother, Keith, and his wife, Rae, one evening. (But) while Millie ultimately backed out of having sex with Keith, Hugh slept with his sister-in-law….Hefner’s thirst for sexual experience became so strong that he even had a one-time homosexual experience. One evening in downtown Chicago he was propositioned and, according to Sellers, he thought, ‘What the hell…’ As far as I know, the guy just gave him (oral sex).’”