“Infinite Jest” is a phrase from Shakespeare’s
Hamlet, a play upon which the novel is loosely based. (Hal is Prince Hamlet, James is Hamlet’s dead father who appears as a ghost, and Avril is Hamlet’s treacherous mother Gertrude. Charles is King Claudius, who in the play is the deceased King Hamlet’s brother but in the novel is Avril’s stepbrother, adding a more explicitly incestuous dynamic to the story.) This important endnote thus brings together many of the threads of the story.