David S. Touretzky is a research professor in the Computer Science Department and the Center for the Neural Basis of Cognition at Carnegie Mellon University. He received a BA in Computer Science at Rutgers University in 1978, and earned a master's degree and a Ph.D. (1984) in Computer Science at Carnegie Mellon University. Touretzky has worked as an Internet activist in favor of freedom of speech, especially what he perceives as abuse of the legal system by government and private authorities. He is a notable critic of Scientology.

Xenu, also called Xemu, is a figure in the Church of Scientology's secret "Advanced Technology", a sacred and esoteric teaching. According to the "Technology", Xenu was the extraterrestrial ruler of a "Galactic Confederacy" who brought billions of his people to Earth in DC-8-like spacecraft 75 million years ago, stacked them around volcanoes, and killed them with hydrogen bombs. Official Scientology scriptures hold that the thetans of these aliens adhere to humans, causing spiritual harm.