With this book, Rodney Orpheus has produced the most significant Thelemic book written this century. The Grimoire of Aleister Crowley adds a key missing fragment to the corpus of Crowley’s Thelemic rituals – a coherent set of group rituals which enhance personal practices and expand effective magical interaction between practitioners. Drawing on unpublished Crowley material, the author has vitalised the rituals with the spirit of Thelemic practice, rather than slavishly following standard formulae. This book is going to end up being standard reading for numerous groups,and is sure to cause a stir, and may even start a revolution.

– David Rankine, author of The Goetia of Dr. Rudd, The Grimoire of Arthur Gauntlet, etc.