Robert Anton Wilson's Cosmic Trigger: Final Secret of the Illuminati

Cosmic Trigger deals with a process of deliberately induced brain change. This process is called 'initiation' or 'vision quest' in many traditional societies and can loosely be considered some dangerous variety of self-psychotherapy in modern terminology. I do not recommend it for everybody. The main thing I learned in my experiments is that 'reality' is always plural and mutable. -- From the Preface