Sara Northrup Hollister, American occultist (d. 1997)
Sara Elizabeth Bruce Northrup Hollister (April 8, 1924 – December 19, 1997) was an occultist and second wife of Scientologist founder L. Ron Hubbard. She played a major role in the creation of Dianetics, which evolved into the religious movement Scientology. Hubbard would evolve into the leader of the Church of Scientology.Northrup was a major figure in the Pasadena branch of the Ordo Templi Orientis (O.T.O.), a secret society led by the English occultist Aleister Crowley, where she was known as "Soror [Sister] Cassap". She joined as a teenager along with her older sister Helen. From 1941 to 1945 she had a turbulent relationship with her sister's husband John Whiteside Parsons, a pioneer in liquid-fueled rocketry and head of the Pasadena O.T.O. Although she was a committed and popular member, she acquired a reputation for disruptiveness that prompted Crowley to denounce her as a "vampire." She began a relationship with L. Ron Hubbard, whom she met through the O.T.O., in 1945. She and Hubbard eloped, taking with them a substantial amount of Parsons' life savings and marrying bigamously a year later while Hubbard was still married to his first wife, Margaret Grubb.

Northrup played a significant role in the development of Dianetics, Hubbard's "modern science of mental health", between 1948 and 1951. She was Hubbard's personal auditor and along with Hubbard, one of the seven members of the Dianetics Foundation's Board of Directors. However, their marriage was deeply troubled; Hubbard was responsible for a prolonged campaign of domestic violence against her and kidnapped both her and her infant daughter. Hubbard spread allegations that she was a Communist secret agent and repeatedly denounced her to the FBI. The FBI declined to take any action, characterizing Hubbard as a "mental case". The marriage ended in 1951 and prompted lurid headlines in the Los Angeles newspapers. She subsequently married one of Hubbard's former employees, Miles Hollister, and moved to Hawaii and later Massachusetts, where she died in 1997.