Set in California during the 1970s, the book features heavy auto-biographical elements and draws inspiration from Dick's own investigations into his unexplained religious experiences over the previous decade.

"[2] In March 1974, Horselover Fat (the alter-personality of Philip K. Dick) experiences visions of a pink beam of light that he calls Zebra and interprets as a theophany exposing hidden facts about the reality of our universe, and a group of others join him in researching these matters.

Kevin turns his friends on to a film, Valis, that contains obvious references to revelations identical to those that Horselover Fat has experienced, including what appears to be time dysfunction.

In seeking the film's makers, Kevin, Phil, Fat, and David—now calling themselves the Rhipidon Society—head to an estate owned by popular musician Eric Lampton and his wife Linda.

In addition to healing Phil's schizophrenic personality split, she tells them that their conclusions about VALIS (which Fat had previously termed Zebra) and reality are correct, and more importantly, that we should worship, not gods, but humanity.

"[7] Umberto Rossi posits that some degree of academic discomfort towards the novel has resulted from uncertainty whether Dick genuinely believed in the more fantastical aspects of the narrative (further supported by the Exegesis which followed).

Dick claimed that VALIS used "disinhibiting stimuli" to communicate, using symbols to trigger recollection of intrinsic knowledge through the loss of amnesia, achieving gnosis.

The most prominent religious references are to Valentinian Gnosticism, the Rose Cross Brotherhood, Zoroastrianism and Buddhism, as well as Biblical writings including the Book of Daniel and the New Testament epistles.

More recent thinkers that are mentioned include the philosophers Pascal and Schopenhauer, the Christian mystic Jakob Böhme, the alchemist Paracelsus, Carl Jung and Sigmund Freud, the Romanian historian of religion Mircea Eliade, and the author and psychologist Robert Anton Wilson.

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 (likely based on David Bowie and Brian Eno respectively).

"The Black Iron Prison" is a concept of an all-pervasive system of social control postulated in the Tractates Cryptica Scriptura, a summary of an unpublished Gnostic exegesis included in VALIS.

[9]VALIS was adapted in 1987 as an electronic opera by composer Tod Machover, and performed at Centre Georges Pompidou, with live singers and video installations created by artist Catherine Ikam.

[10] On February 1, 2004, Variety announced that Utopia Pictures & Television had acquired the rights to three of Philip K. Dick's works: Flow My Tears, The Policeman Said, VALIS, and Radio Free Albemuth.

[14] Portuguese double bassist Hugo Carvalhais's 3rd album Grand Valis (Clean Feed Records 2015) is inspired by Dick's book.