Dayworld is a trilogy of science fiction novels by Philip José Farmer, inspired by his own acclaimed short story "The Sliced-Crosswise Only-On-Tuesday World". They are set in a dystopian future in which people are allowed to live only one day of the week. For the rest of the six days they are "stoned", a kind of suspended animation. The novels focus on a man, Jeff Caird, who is a daybreaker: someone who lives more than one day a week. As the series progresses, the main character seems to be suffering from dissociative identity disorder. The novels comprising the trilogy are: