Memnoch the Devil is the fifth novel in Anne Rice's The Vampire Chronicles following The Tale of the Body Thief. In this story, Lestat is approached by the devil himself and offered a job.
Memnoch (the devil) takes Lestat on a whirlwind tour of Heaven, Hell, and the main epochs in the evolution of the Universe. The tour is an effort by Memnoch to convince Lestat to join him in a noble quest. In his journey, Memnoch explains to Lestat that he is indeed not evil but merely working for God by ushering lost souls into Heaven. Lestat is left with the confused choice of whether he will help the devil or not. After all, wouldn't he really be helping God?