I came in in 1968, we studied the "truth book" (but really it was the "lie book"). Previously they would study with you as long as you were still willing, but at that time they started saying if you hadn't progressed to at least meeting attendance in six months, they were supposed to dump you. Every thing you needed to know was in that book. They book was designed to give you a sense of urgency and make you afraid. Using fear and intimidation, and claiming to be the only path to salvation is a sign of a cult.