Revision. 
 This might turn out to be one of those reviews I write over and over. 
 Perhaps such a novel -- equal parts fine-focused lens, social/personal mirror, and harshly distorting prism -- just demands this endless rethinking. 
 So what is Dhalgren? 
 It is a deft cultural analysis, part perfectly current, part more dated 60s/70s scrutiny that is nonetheless perceptive and interesting. 
 It is a probing of time and perception laid out in dilating asymptotic fade contracting sudden into action. Or perhaps a mobius strip whose returning loop falls away infinitely. Or perhaps infinite loops gathered in a singularity. 
 It is the story of a city that falls appart in unclear crisis, tears a hole straight through America, and becomes a dreamlike non-place: smoke-swept, flame-licked, partially abandoned and wholly forgotten, socially volatile and facilitative and instructive. 
 It is a narrative labyrinth whose many questions and vaguely suggested answers, in the way of many such intricate dream-voyages, are less interesting and significant than the paths traced between them by the vivid raw conjuration of the words and action. 
 Delany is full of (and unafriad to face) Big Ideas. He's also a fantastic and versatile prose stylist. He's also extremely readable. There are admittedly some less vital slumps, but the peaks are precipitously high (as in the near-perfect novella of a third act "House of the Ax"). And even those slump sections seem accounted for by Delany's designs -- I feel like the plot structure models physics equations, as the action approaches an asymptote at one point, then punches through a discontinuity into the infinite before flipping back around. All this evades me slightly still, it is too big to be fully glimpsed at once, a novel bursting with the force and potential of fiction. 
 And as an aside: I often refer to The House of Leaves as "applied post-modernism", for its meshing of decades of formal and conceptual developments with brisk and frequently gripping genre toying (itself a hallmark of post-modernism, I suppose). But Delany's sprawling social treatise accomplished a similar feat 25 years early, complete with layered symbology and layered typographical/narrative mysteries. 
 Echoes back: to Borges and probably a bunch of groundbreaking 60s new wave sci-fi I haven't read (suggest please). 
 Echoes forward: to early Lethem (particularly Amnesia Moon), and usual canon-aware suspects Danielewski and (D.F.) Wallace.