Dianetics

Dianetics is the first part of the Scientology Bridge. Its focus is the self-help therapy called auditing, purported to produce the state of Clear.

While the division isn't hard and fast, in general, Dianetics deals with the reactive mind, while Scientology deals with the soul (thetan) and eternity.

As one example of the overlap, Dianetic auditing often involves recall of incidents from past lives.