My latest Deep Cut in a Lovecraftian Vein looks at the Book of Dzyan in the Mythos. Clark Ashton Smith forms a pretty essential part of the epistolary record here - which I didn't go into in full because the post was already pretty damn long. I think it's interesting to consider the influence Theosophy had on CAS - which is, as he put it, that he took a few basic concepts and spun them out with his own imagination. He never tries, to my knowledge, to actually incorporate many actual elements from Theosophical texts (of which he doesn't appear to have been familiar with many, except Sinnett's Esoteric Buddhism). So for example, CAS never tries to work in "root-races" as a concept in any real degree.