Debunking Carlos Castaneda
I read some of the books as a teenager and was affected by them. Castaneda's writing communicates a sense of wonder that hearkens back to the religious texts that have informed many cultures over time. And like Castaneda, Jesus really existed, and presented eye-opening ideas that became popular in their cultural moment, and have lived on. Now, millions believe in the absurd canard that Jesus "...descended into hell. On the third day he rose again."
If that fictional belief allows people to expand their imaginations beyond the humdrum daily life, then so be it. Marxism has the same "big idea," that there is an inevitable, transhistorical liberation of working people. It's the essential component of all religions -- that there is something bigger and better, unimaginable, connected to practice and belief.
Castaneda may indeed have been, at a personal level, a small-time version of Jim Jones (above), but he leaves texts that communicate a sense of wonder to the reader; that our imaginations may be expanded. That's a good enough contribution to me, albeit fictional.