Very sorry to learn of Disch's suicide on July 4.
Other bloggers are sharing their personal reflections (see update below). I had just posted something on him in May, concerning his 1980s computer/interactive fiction text adventure Amnesia.
Camp Concentration, On Wings of Song, The Dreams Our Stuff is Made Of, and The MD grabbed me hardest of his books (have read others but those are my "keepers"). His essay on Philip K. Dick's first novel Solar Lottery* I have read and reread. It is a great piece of criticism. He's totally on throughout, as if writing a brief to the highest court of literary appeal (when in fact it was just a forward to the Gregg Press edition of SL). He never stints on Dick's flaws but strikes the perfect balance of "high" and "low" literary reference to convince you of the man's importance (if not the novel's under scrutiny). Here is the last para:
This is not to say that readers will find no formal pleasure in Dick's novels, that it is all a matter of snuffling about for truffles of Meaning, as I've been doing here. But his commitment to an aesthetic of process means that, by and large, whatever he writes is what we read. There is no turning back to rethink, revise, or erase. He improvises rather than composes, thereby making his experience of the creative process the focus of his art. This is not a novelty, of course. It is the wager of Scheherezade, too, that she can be interesting and authentic absolutely all the time, and this tradition of the novel is as old and as honorable as the more Flaubertian idea of the novel-as-prose-poem that presently holds sway in academia. Within this tradition Dick is one of the immortals by virtue of the sheer fecundity of his invention. Inevitably there are dull patches, days when his typewriter refuses to wake up, but on the whole these are few, and the stretches of song, when they come, are all the more remarkable for being, so visibly, the overflow of a spirit that from Heaven, or near it, pours its full heart in profuse strains of unpremeditated art.
Like the French, but unlike U.S. snobs such as Gary Indiana, Disch clearly saw something in Dick. Perhaps in death Disch will have advocacy this full-hearted for his own writing. (I can't speak for his poetry but apparently Disch thought the New Yorker was snubbing it because he was a lowbrow science fiction writer. What a world.)
*"Toward the Transcendent: An Introduction to Solar Lottery and Other Works," Disch's 1983 rewrite of a 1976 essay. The rewrite appears in Olander & Greenberg's Writers of the 21st Century: Philip K. Dick (New York: Taplinger Publishing)
Update: Other thoughts on Disch have been compiled by Edward Champion and Enter the Octopus.