Bill Masters was an American gynecologist and sexologist, best known for his pioneering research on human sexuality. Along with his research partner, Virginia Johnson, he conducted groundbreaking studies in the 1950s and 1960s that explored sexual response and behavior. Their work led to the development of the Masters and Johnson model of sexual therapy, which has influenced both clinical practice and sexual education. Masters was born on December 27, 1915, in Cleveland, Ohio, and earned his medical degree from the University of Rochester. He published several influential books, including "Human Sexual Response" and "Human Sexual Inadequacy," which helped to demystify sexual issues and promote a better understanding of human sexuality. He passed away on February 16, 2001.