Unt i l a very few years ago, it was unusual for those few social scientists studying male homosexuality to make anything more than a cursory, oblique and often rather embarrassed mention o f the sexual practices engaged in by the subjects o f their study. Rather, attention was typically focussed on the psychological epigenesis o f a homosexual orientation or the social organization o f gay lifestyles. It has, therefore, been a strange experience, over the last few years, to hear in conferences throughout the world, scientists from many disciplines addressing large and growing audiences on the intricate and intimate details o f male homosexual practice. For today, there are reputations to be made, grants to be obtained and academic preferment to be won by describing activities that ten years ago were the province of the academic maverick and twenty years ago the subject o f criminal sanction.