I re-read the really good ones. This is one.
Rather like "A Clockwork Orange" in that the chunk of it is utterly repellent; I really wasn't sure I wanted to continue with it after the first chapter or two. Then, it hypnotized me.
It takes a while to appreciate that Sumner Kagan's depravity as a youth are an important foundation for the story, and he does not become a nice person quickly or suddenly, perhaps not at all. His evolution is more about pride, honor, and understanding himself. The author's fantasy post-apocalyptic world is vivid, weirdly believable, and worked deftly into cosmological observations and theory. Sumner and the marginally human and non-human characters are vividly drawn, and the author's prose is both poetic and lyrical, contributing much to the feel of this world.
Some aspects are prophetic: the predications of climate change aren't based on what put us where we are today -- that's where the cosmological stuff about the rotation of star systems and the galaxy come in -- but the tangible environmental impact is quite like what we are seeing during the first quarter of Century 21.
You'll hate the protagonist for much of the book. He has suffered greatly and has himself done terrible things. But I couldn't help being absorbed by his character, and cheering him through the conflicts as he finally recognizes his mission and destiny. Great read; have loaned my copies to select friends. Not everyone is able to see the beauty of this fine work...
One other point: This is a standalone epic novel. The books that comprise the rest of the "Radix Tetrad" have some references and links that relate them to this tale, but ... in my opinion, while "In Other Worlds" (the 'next' book) is trippy fun and even more fantastic, none of them comes close to the integrated remarkability and re-readability of "Radix", which will forever be a favorite.