I've been reading the work mentioned in the original post of this thread, George Grimm's The Doctrine of the Buddha, which I had only previously read the introduction of and I have to say I am amazed at how high quality this work is. In terms of an exegesis of earliest Buddhism, I think Grimm's work and Evola's Doctrine of Awakening should be the two essential reads for anyone seriously interested in the topic. While I have yet to finish the book, I came across a passage earlier today that I just had to share. Due to the fact that the PDF I have isn't text based but image based, and because I am too busy/lazy to retype the passage, I copied the image instead. Certainly worth a read: So, while both Grimm's and Evola's works on the topic are certainly not "easy" introductions, I think reading them along with general collections of the Pali Cannon, such as FL Woodward's great book Some Sayings of the Buddha provide the best possible basis for understanding "original" or "Aryan" or "basic Buddhism", which of course is a basis that should be well understood in order to better understand either Mahayana or Buddhist esotericism.