This Thelemic Law of Rabelais was revived by Aleister Crowley in 1904 when Crowley wrote The Book of the Law . This book contains both the word Thelema in Greek as well as the phrase `` Do what thou wilt . '' Aleister Crowley himself wrote in The Antecedents of Thelema , ( 1926 ) an incomplete work not published in his day , that Rabelais not only set forth the law of Thelema in a way similar to how Crowley understood it , but predicted and described in code Crowley 's life and the holy text that he claimed to have received , The Book of the Law .