VALIS is a 1981 science fiction novel by Philip K. Dick. The title is an acronym for Vast Active Living Intelligence System, Dick's gnostic vision of one aspect of God.
It is the first book in the VALIS trilogy of novels including The Divine Invasion (1981), and the unfinished The Owl in Daylight. Together with Dick's last book, The Transmigration of Timothy Archer (1982) (thematically related to the unfinished trilogy and included in several omnibus editions of the trilogy as a stand-in for the unwritten final volume), VALIS represents Dick's last major work before he died. Radio Free Albemuth, a posthumously published earlier version of VALIS, is not included as a component of the VALIS trilogy.