a course in Scientology which centered around the basic books by L. Ron Hubbard and the Professional Course Booklets (also known as the 50 Course Booklets). These booklets were compiled from transcripts of lectures given by Ron during the spring and summer of 1952. The tapes of these lectures were supplemented by the booklets and together they formed the materials of the Professional Course. The course was six weeks in length and at the end of each week the students took a n examination on what they had covered. —PDC Volume 7 Approved Glossary