Super interesting concept, but I don't think it has aged very well. This book was written at a point where the idea of space exploration and aliens and such seemed more fresh and new than they do now. But I couldn't help reading the book (which is supposed to be about the future) and thinking "wow, this feels old".
I got it for free at some point (or maybe I bought it as part of a Humble Book Bundle?) and when viewed in the light... it was alright!
Again, it did have a cool idea behind it. SPOILER: the maximum intelligence of a being is controlled by the "zone" that it's in. As you get to the outer zones, the beings get less intelligent and their technology less sophisticated - and towards the "Trancend" you get super-intelligences that approach gods.
So cool idea, right? But the book is about a bunch of dog people that inhabit stone castles and form packs where multiple beings sort of form hive minds, and they take some human children hostage. It's neat - except again, it feels old today.
I still liked it, and maybe more than average. I'm gonna go with 4 stars out of 5 - though 3.5 might be fair too.