The first book in Philip K. Dick's defining trilogy (followed by "The Divine Invasion" and "The Transmigration of Timothy Archer"), "VALIS "is a disorienting and bleakly funny novel about a schizophrenic man named Horselover Fat (who just might also be known as Philip Dick); the hidden mysteries of Gnostic Christianity; and reality as revealed through a pink laser. "VALIS" is a theological detective story, in which God is both a missing person and the perpetrator of the ultimate crime. Taking place in the same universe as Dick's soon-to-be-published "Exegesis, " "VALIS" is a dense novel, but one that is absolutely essential to understanding the author's off-kilter worldview.