This book had its origin in a series of lectures delivered in the spring of 1965 at a number of universities and colleges in the United States and Canada. For publication, the lectures have been completely revised and considerably expanded. Gnosticism first appeared and attracted the attention of scholars as a movement within the Christian religion, and for a long time it was regarded as a purely Christian movement, a perversion of the Christian faith into a speculative theology. It is not the separate elements themselves which are Gnostic, but the total synthesis, the system, into which they are combined. - p. [vii], 4-5.