Occultism's most famous name, self-marketed as the wickedest man alive.
Documented
The paper trail is enormous
Mountaineer, poet, chess player, founder of Thelema, author of Magick in Theory and Practice. His diaries, letters, and libel cases are extensively archived. In 1934 he sued over claims he practiced human sacrifice and lost, bankrupting himself on the record.
Assessment: Documented beyond most historical figures twice his significance. The man kept receipts.
Stories
The wickedest man in the world
The tabloid version, which he authored: satanist, traitor, sacrificer of children, curses that killed rivals, a haunted Loch Ness house later bought by Jimmy Page. Paul McCartney's Beatles put him on the Sgt. Pepper cover.
Assessment: Mostly fabrication, and the fabrication is the documented part. He never sacrificed anyone; he did sacrifice every reputation, including his own, for the legend.
Interesting claims
The prophet of the new aeon
The believer's claim: in Cairo in 1904 a voice called Aiwass dictated The Book of the Law through him, announcing a new era where each person's true will is the only law, and the twentieth century's individualism proves the prophecy.
Assessment: The dictation is documented as event; the source is the question. Skeptics note the book reads exactly like Crowley, while followers call that the point. The archive notes only that the prophecy, like all successful ones, describes whatever happened next.
Sources and further reading
Crowley, The Confessions, Symonds and Grant ed.
Kaczynski, Perdurabo (2010), the standard biography
Crowley, The Book of the Law (1904)
Worth asking
If you manufacture your own demonization and the world complies, who wrote the story?