William Sims Bainbridge (born October 12, 1940) is an American sociologist who currently resides in Virginia. He is co-director of Cyber-Human Systems at the National Science Foundation (NSF). He is the first Senior Fellow to be appointed by the Institute for Ethics and Emerging Technologies. Bainbridge is most well known for his work on the sociology of religion. Recently he has published work studying the sociology of video gaming.
Bainbridge began his academic career at the Choate Rosemary Hall preparatory school in his birthstate of Connecticut. He went on to matriculate at Yale University and at Oberlin College, and finally settled on Boston University. He studied music and became a skilled piano-tuner. In his free time, he constructed harpsichords and clavichords with the "Bainbridge" name, which still exist in a few households.
Bainbridge received his Ph.D. in sociology at Harvard University and went on to study the sociology of religious cults. In 1976 he published his first book, The Spaceflight Revolution, which examined the push for space exploration in the 1960s. In 1978, he published his second and most popular book, entitled Satan's Power, which described several years in which Bainbridge infiltrated and observed the Process Church, a religious cult related to Scientology. The study was one of the last of this type of academic studies done before new rules were introduced restricting unregulated participatory observation and study.