Memnoch the Devil is a novel by Anne Rice in which the concepts of good and evil are questioned. Through Memnoch's interactions with God and Lestat, all of the characters question their motives, and they search their souls to try to determine whether they are truly good people or not. Memnoch the Devil is a very interesting addition to Anne Rice's Vampire Chronicles.

Lestat is a vampire who is tracking a victim that he has taken a special interest in, a drug lord, murderer and art smuggler named Roger. During his hunt he has become aware of another presence following him as well and has become frightened of what may be tracking him. For some reason he believes that this may be the Devil that is tracking him and he calls upon his close friend and fledgling, David, for comfort and advice. David advises that perhaps the events taking place may have something to do with the victim of choice, or with the victim's daughter, Dora, a religious leader. David actually feels more as though Lestat may be loosing his mind.

When Lestat takes his victim, something unusual occurs that shakes Lestat. The victim first talks to Lestat, which is something that no other victim has been able to do. Also, Roger comes back to Lestat to tell him his life's story, make corrections to the gaps that Lestat has been made aware of and to ask that Lestat watch over his daughter. Lestat accepts the responsibility, but must also deal with his own personal feelings for Dora, as well as the past. Lestat 's past with women causes him trouble in this area in keeping his promise. Lestat's stalker turns out to confront him in the middle of his living up to this new responsibility and he must attempt to fulfill his promise to Roger and take on the challenge that has been placed at his feet.

Memnoch, the Devil has come to ask for Lestat's assistance as his first lieutenant. Lestat must now decide if he will accept the Devil's proposal and keep his soul. Furthermore, Lestat has to reconcile his religious ideas with the true history of the beginning of the world and the parts that both God and the Devil play in the world that exists and the afterlife. He is given the opportunity to find out the answer to the very question that has plagued mankind since the beginning, but once he does have the answers, will he be able to choose a side, and if so, will it be the right one?

Lestat is taken to Heaven and to Hell, as well as to the beginning of time and even to the crucifixion of Christ to witness the events as they truly happened and made his decision based on what he witnesses.