There is some good information in the first 8 chapters, but the last few chapters seems
Like it should have been a completely separate book on Christian Gnosticism. The audiobook version, while true and accurate in its information, contains many mispronounced words, showing that the author is not experienced in the cultures about which he is teaching.
For books on psychedelics and religion, I’d recommend The Archaic Rwvival by Terence McKenna or Persephone’s Quest by Wesson, Kramisch, Ott, & Ruck.
For the gnostic gospels, you can read them directly, or read Elaine Pagel’s book on their discovery and role in religion.