VALIS is the first book in the VALIS trilogy of novels including The Divine Invasion (1981), and the unfinished The Owl in Daylight. The Transmigration of Timothy Archer (1982) is thematically related to the unfinished trilogy and was included in several omnibus editions of the trilogy as a stand-in for the unwritten final volume. Together with his thematically related final novel, VALIS represents Dick's last major work before he died. Radio Free Albemuth is considered an earlier version of VALIS, and is not included as a component of the VALIS trilogy.
During this time he begins writing his 'tractate' which is a commonplace book of amalgamated philosophies and concepts Dick had compiled in an attempt to explain this experience.
Even though the book is written in the first-person-autobiographical, for most of the book Dick treats himself and Fat as two separate characters; he describes conversations and arguments with Fat, and harshly if sympathetically criticizes his opinions and writings. The major subject of these dialogues is spirituality, as Dick/Fat is/are ostensibly obsessed with several religions and philosophies, including Christianity, Taoism, Gnosticism and even Jungian psychoanalysis, in the search for a cure for what he believes is simultaneously a personal and a cosmic wound. Near the end of the book the messianic figure, incarnated by the child Sophia (a name associated with Wisdom in many Gnostic texts), cures him (temporarily), and the narrator describes his surprise that Horselover Fat has suddenly disappeared from his side.
VALIS has been described as one node of an artificial satellite network originating from the star Sirius in the Canis Major constellation. According to Dick, the Earth satellite used "pink laser beams" to transfer information and project holograms on Earth and to facilitate communication between an extraterrestrial species and humanity. Dick claimed that VALIS used "disinhibiting stimuli" to communicate, using symbols to trigger recollection of intrinsic knowledge through the loss of amnesia, achieving gnosis. Drawing directly from Platonism and Gnosticism, Dick wrote in his Exegesis: "We appear to be memory coils (DNA carriers capable of experience) in a computer-like thinking system which, although we have correctly recorded and stored thousands of years of experiential information, and each of us possesses somewhat different deposits from all the other life forms, there is a malfunction - a failure - of memory retrieval."
At one point, Dick claimed to be in a state of enthousiasmos with VALIS, where he was informed his infant son was in danger of perishing from an unnamed malady. Routine checkups on the child had shown no trouble or illness; however, Dick insisted that thorough tests be run to ensure his son's health. The doctor eventually complied, despite the fact that there were no apparent symptoms. During the examination doctors discovered an inguinal hernia, which would have killed the child if an operation was not quickly performed. His son survived thanks to the operation, which Dick attributed to the "intervention" of VALIS.
Another event was an episode of xenoglossia. Supposedly, Dick's wife transcribed the sounds she heard him speak, and discovered that he was speaking Koine Greek-the common Greek dialect during the Hellenistic years (3rd century BC-4th century AD) and direct "father" of today's modern Greek language- which he had never studied. As Dick was to later discover, Koine Greek was originally used to write the New Testament and the Septuagint. However, this was not the first time Dick had experienced xenoglossia. A decade earlier, Dick claimed he was able to think, speak, and read fluent Latin under the influence of Sandoz LSD-25.
The UK edition of VALIS also included Cosmology and Cosmogony, a chapbook containing selections from Dick's Exegesis.
The action of VALIS is set firmly in the American popular culture of its time, with references to the Grateful Dead, Frank Zappa and Linda Ronstadt as well as the fictional rock musicians Eric Lampton and Brent Mini. However, the novel also contains a number of high culture references such as the poets Vaughan, Wordsworth and Goethe, and the classical composers Handel and Wagner. In particular, the novel contains several extended discussions about Wagner's metaphysical opera Parsifal.
The Black Iron Prison was the founding of a line of thought in Discordian philosophy.
In 2004, on the occasion of the 30th anniversary of Philip K. Dick's alleged epiphany, described in the Exegesis and dramatized in VALIS, an art exhibition was organized in Vienna by multimedia artist's group XDV, which had several interactive artworks inspired by the descriptions of his experiences.
On February 1, 2004, Variety announced that Utopia Pictures & Television had acquired the rights to produce three of Philip K. Dick's works: Flow My Tears, The Policeman Said; VALIS; and Radio Free Albemuth.