When I was introduced to metaphysics around the age of 20, the "bible" for metaphysical thought in concern to understanding the nature of reality was a book by Jane Roberts called The Nature of Personal Reality: Specific, Practical Techniques for Solving Everyday Problems and Enriching the Life You Know
The premise of this book is the simple but powerful idea that we create our realities from our beliefs. This puts the responsibility upon us as individuals to become conscious of our beliefs so that we can decide to change them if needed to ones less limiting that might be causing problems in all areas of our lives.
I quote Seth in The Oracle of the Phoenix with some of the material coming from his introductory book Seth Speaks.
Below are audio excerpts from this book that will shed light on this controversial idea of channeled material and provide context around these revolutionary teachings. The volumes of work produced by Seth and Jane Roberts can be found in the Yale Library.