This is the sequel to a Fire Upon the Deep, one of my favorite books. The original book had two parts. One deals with a desperate attempt to flee a hugely evil computer program that is taking over the universe, and the other part deals with a marooned ship full of children on a planet populated with intelligent packs of dog-like creatures.
I am one of the few people who liked the conflict with the evil computer program known as The Blight. Children of the Sky deals with what happens to the children and the packs, so I was disappointed.
Vinge has created a very rich cast of characters and some very frightening conflicts. There is a part of the book where I think he is making his protagonists suffer just a little too much, but the resolution is very satisfying.
If you enjoyed the packs storyline in Fire Upon the Deep then you will like this book a lot. If, like me, you are interested in how the universe deals with the blight program, then you will have to wait for the next book. Vinge clearly signals that the third, and probably last, book is on the way. He takes two to three years to write a book, though.