Book: Scientology 0-8
Hubbard claims Scientology raises IQ.
As people come into Scientology (and they are coming in, in very swiftly increasing numbers, all over the world), normally what they do first is read a book, and then they may read quite a few books, and go around and about Scientology for some time.
They attend some of the introductory courses, and then they get some processing—often beginning with Dianetics. Their IQ goes up, their abilities increase, they become more capable of handling their lives.
Hubbard, L. R. (1951). Scientology 0-8 The Book of Basics (1988 ed., pp. 13-14). Los Angeles: Bridge Publications, Inc.