Mary Cover Jones was a well-known developmental psychologist specializing in child and adolescent development. She graduated from Vassar College in 1919 then attended Columbia University where she earned her master's degree in 1920 and doctorate in 1926. In 1920, she married her fellow psychology graduate student, Harold Jones.

Cover Jones is often referred to as "the mother of behavior therapy" for her graduate work developing and testing techniques to reduce or eliminate phobias in children. Her best-known case was of a three-year-old boy, Peter: Jones, M.C. (1924). A laboratory study of fear: The case of Peter. Pedagogical Seminary, 31, 308-315.

Cover Jones was best able to reduce Peter's fear of rabbits through what she called "direct conditioning," a method similar to the behavior therapy known today as "systematic desensitization."

In 1927 her husband, Harold, accepted a dual position at the University of California at Berkeley as a faculty member in the Department of Psychology and Director of the new Institute for Child Welfare. Cover Jones became a research assistant for the institute and was especially involved in the Oakland Growth Study. This longitudinal study followed a group of fifth and sixth graders, reassessing them at ages 38, 48, and 60. In fact, Cover Jones was 83 when she conducted her final interviews in 1980. Over the course of her career Cover Jones contributed 100 or more publications from the Oakland Growth Study alone. She also served for a time as President of the American Psychological Association's (APA) Division of Developmental Psychology, and in 1968, was honored by APA with the G. Stanley Hall Award for her lifetime of achievement in developmental psychology.