James Beryl Maas (born 1938) is an American social psychologist and retired professor. He is best known for his work in the field of sleep research, specifically the relationship between sleep and performance. He is best known for coining the term "power nap". He holds a B.A. from Williams College and an M.A. and Ph.D. from Cornell University. Maas has also produced numerous film specials on sleep research for PBS, BBC, and others.
For 48 years Maas taught psychology as a professor at Cornell University. In January 1995 a Cornell University ethics committee recommended sanctions against Maas for sexual harassment. After the College's Senior Sexual Harassment Counselor determined that the complaints against plaintiff had merit, hearings were held before the College's Professional Ethics Committee. On June 23, 1995 the Cornell University Administration published a press release that found Maas had neither sought "an intimate sexual relationship with any of his students nor...engaged in the physically abusive behaviors often associated with the term 'sexual harassment.'"
Maas continued as a distinguished professor until his retirement on December 31, 2011. He currently serves on the advisory board of American Sleep Association.