In this chapter I will tackle a subject that has hitherto been almost completely ignored by scholars of Crowley: namely, the interest that conspiracy theorists and traditionalist circles took in him. I use the term “conspiracy theory” to indicate those theories that spread throughout Europe especially between the late eighteenth and mid-twentieth centuries, postulating the existence of an international conspiracy arranged by an unknown and mysterious elite, the purpose of which is to gain power over the whole world. As Joscelyn Godwin has pointed out, “conspiracy theory is anathema to the historian, but indispensable to the history of occultism”. This is undoubtedly true, given that conspiracy theories have so often germinated and developed in esoteric and occult circles.