Johnson and gynecologist William Masters, whom she would later marry, observed more than 700 men and women from the St. Louis area to document the way humans responded physically to sexual arousal. Their book on the topic became a best-seller.
In an interview on St. Louis on the Air in May 2009, biographer Thomas Maier told host Don Marsh that while Masters was the star, Johnson was responsible for their success.
“She’s the one who convinced so many women to be volunteers in this work. She’s the one whose native understanding of human nature about sexuality, because she took all the histories from patients, led to the therapy that was remarkably successful.Masters was forever indebted to her.”
Maier says despite their work on love and sex, the marriage between Masters and Johnson was largely a business arrangement. They divorced in 1992. Masters died in 2001.