Four Phases of Human Sexual Response
In this book, they identify and describe four phases in the human sexual response cycle: excitement, plateau, orgasm, and resolution. By this point in time, the generally repressive attitude toward sexuality was beginning to lift and the book found a ready audience. Masters and Johnson were quickly catapulted to celebrity status as their book became a best seller.

During this period, Masters divorced his first wife and Masters and Johnson wed. In 1970, they published "Human Sexual Inadequacy", which was concerned with the treatment of impotence, premature ejaculation, frigidity and other sexual problems.

In the wake of these two publications, the field of sex therapy—the clinical treatment of sexual problems — was born. Throughout the 1970s and 1980s, Masters and Johnson continued their research and publication efforts. Their book "Homosexuality in Perspective", which described the sexual responses of gay men and lesbians, was published in 1979.

Myths About Homosexuality Debunked
In this book, Masters and Johnson debunked the notion that homosexuality is a mental illness. However, their claimed ability to change the sexual preferences of homosexuals who wished to change produced considerable criticism from the gay community and from other sex researchers. Their final collaboration, "Heterosexual Behavior in the Age of AIDS," published in 1988, was not well received because of its criticism of the general need for safer sex practices (including condom use) in heterosexual relationships.

Based on their studies of problems in sexual fulfillment, Masters and Johnson established a clinic for the treatment of sexual problems in St. Louis. Many of the students who trained at their center went on to establish practices in sex therapy around the country. Additionally, many of the therapeutic practices begun at the clinic, such as assisting couples to more fully experience and focus on basic physical sensations, are central to contemporary sex therapy nationwide.

One of the key issues of concern to Masters and Johnson was the issue of impotence. In "Human Sexual Inadequacy", Masters and Johnson maintained that 90 percent of impotence — the persistent inability to achieve or maintain an erection — is psychological in origin. Even in older men, according to Masters and Johnson, emotional issues rather than organic problems are the main causes of impotence.