The Transsexual Phenomenon is a medical textbook published by American endocrinologist and sexologist Harry Benjamin in 1966 with The Julian Press. The text is notable for its examination of transsexualism not as a psychological issue, but rather as a somatic disorder that should be treated through medicine. Benjamin argues that transvestism and transsexuality are a spectrum of conditions, requiring different treatments that ranged from hormone replacement therapy to surgical intervention (such as castration).