I'm rereading Philip K Dick's novel Valis, which I studied as part of my doctoral thesis. Dick isn't the kind of writer you can avoid if you're researching theological themes in science fiction, and Valis is, along with The Divine Invasion, Dick's most overtly theological work.
Fortunately, I simply can't get enough Dick. Do Androids Dream..., A Maze of Death, Ubik... Valis is perhaps not his most accessible novel - you certainly won't enjoy it if religious ideas leave you bored to tears - but for the sheer scale, complexity and outrageousness of the ideas involved it's among the best of his novels. The experience of reading it admittedly resembles being followed by a hypermanic street lunatic shouting biblical exegesis in your ear, but it's very entertaining exegesis.
In Valis, at least according to the speculations of the protagonist Horselover Fat (who's as transparent a Dick-substitute as you're likely to find outside a branch of Ann Summers), the Universe is the domain of an insane and evil Old Testament God, but is in the process of being subverted and subsumed by the benevolent and liberating New Testament God, the Logos. (That's the briefest, baldest summary. There's a lot more about three-eyed aliens, symbiotic plasmates, and God getting accidentally buried for two thousand years at Nag Hammadi.) It's a Gnostic worldview, albeit a Christian Gnostic one, and three-eyed aliens aside it's one I can't help having some sympathy with.
In fact Valis presents a theology in which Dick firmly believed, having had it communicated to him by God from a satellite in beams of pink light during February and March 1974. (This was shortly after the KBG began to send him threatening letters, and eleven years after he was haunted by a gigantic metal face glaring down at him from the sky whenever he stepped outside. Fascinated as he was by the nature of reality, Dick was not the most adept of human beings at distinguishing it from the other stuff.) The astonishing thing is that he nevertheless maintains a degree of ironic detachment which allows the reader of Valis to laugh at Horselover Fat just as often as they gawp at his latest revelation. Indeed, although Dick begins the novel by explaining that Fat is Dick himself, presented in the third person for objectivity, by the halfway point Fat is objectified to the point that the two of them meet socially and have frequent conversations, and Dick is commenting continually on how screwed-up Fat has become.
Incidentally, to maximise the comedy potential of the surname "Dick", one needs to use it in combination with that of Michael Moorcock. I leave this as an exercise for the reader.