The Crystal World is a science fiction novel by English author J. G. Ballard, published in 1966. The novel tells the story of a physician trying to make his way deep into the jungle to a secluded leprosy treatment facility. While trying to make it to his destination, his chaotic path leads him to try to come to terms with an apocalyptic phenomenon in the jungle that crystallises everything it touches. Ballard previously used the theme of apocalyptic crystallisation in the 1964 short story "The Illuminated Man" (included in The Terminal Beach), which is also set in the same locations.