From a rich, insightful, and fascinating review by Roger Bellin of Samuel Delany's Through the Valley of the Nest of Spiders:
It is certainly possible to find worthwhile the effort it takes to attempt the broadening of one's libidinal sympathies — the way a psychologically realistic novel can demand our sympathy with someone else's life and thoughts, this one demands our sympathy with his sexual desires. If science fiction, in Darko Suvin's definition, is the genre of "cognitive estrangement," then the pornographic first half of TVNS is a work of libidinal estrangement: the novel's alienating effect bears on its reader's desires, not his rational mind.
[...]I'm still reading the book, slowly and with, frankly, awe, but everything Bellin says fits well with my reading so far.
Rather than just cataloguing its protagonists' sex acts, TVNS gradually becomes a psychologically complicated novel about what they've learned from them — a reflection, through a host of little narrated daily incidents, on the ethical lessons that a life of joyous perversion has taught Eric and Shit. Sometimes it almost, implicitly, seems like a manifesto for a broad and catholic vision of queer politics; and the novel's real utopia might, finally, have less to do with the imagined community of the Dump than it does with the people themselves, and the practice of loving each other that they've discovered and worked out.
More later, once I've reached the last page of the book...
Update: And now Steven Shaviro is as insightful as always, and offers an impressive first paragraph:
Samuel R. Delany’s new novel, Through the Valley of the Nest of Spiders, is over 800 pages, which makes it the longest book he has ever written (even longer than Dhalgren). It is also one of the best novels by anyone that I have read in quite a long time. Indeed, I would go so far as to say (as I already put it on Twitter) that it is the best English-language novel that I know of, of the 21st century so far.