I think most folks that are already interested have a fairly cursory knowledge in mysticism re: the big 3 (Gnosticism, Qabbalah, & Sufism at least) and how they became en vogue in the Victorian and Edwardian eras and again in the 1960s. I suspect periods of revival make it a little difficult to separate historical fact from crafted fiction (looking at you, Crowley) maybe even for historians, though that's another subject perhaps.

I know that they all share common origins in early Abrahamic cults and Hermeticism, so I really feel like that mystery is somewhat solved. Leaving aside the beaten to death topic of Druids (it's my understanding we know next to nothing about them despite what many claim) I'm far more interested in the stuff we get little to no exposure to on my side of the Alps. Eastern mysticism comes to us often as either a caricature of ignorance (such as in popular films) or a caricature of convenience (your classic new ager's source of income).

Rasputin, for instance, is often referred to as a magician or sorcerer but of what? Was his mysticism post-Christian or wholly invented? Gogol's evil sorcerer is clearly pre-Christian but his dark lord is trusted to the reader to know and never explained. Then in the orient we have loads of myths of powerful sorcerers trapping or freeing demons seemingly willy-nilly but we never get more explanation for that than you can fit in a short prologue to a film. Is this ancient Shintoism or does it predate it?

What do we know (as with the Hermetic roots of the western mystic) and what has been lost to time that draws charlatans with false histories (as with the Druids)? And, also, is there any explanation more concrete than Jungian philosophy for how the Inuits and the Greeks (and everyone in between) seemed to have invented nearly identical monsters in many cases with no apparent cross-cultural contact?

Perhaps this is too broad for /r/AskHistorians, but where does one start?