Read 2/2013, reviewed 4/21/2013
This book is Asimov at his best. It’s a great premise with fully realized characters, human and alien. One of my biggest criticisms of SF is the treatment of aliens as cartoonish. Asimov’s aliens are not. They are well developed characters, whose world view and morality are appropriate in and challenged by their own circumstances.
The book is divided into three parallel sections. The theme is similar in each. There is an establishment which is flawed. It is controlled by one or several entities to keep the status quo. One person recognizes the flaw and its catastrophic implications, works to undermine the establishment, and save the universe.
One of my favorite parts of this book has to do with the way the parallel universes communicate with each other. The complexity of the communication drives the tension to enormous heights. The buildup and conveyance of each message, and their deciphering and understanding drives the story.
I gave this book 4 stars. I knew I was reading a great book from the first few pages. It coalesced for me upon beginning the second section. This book is great SF.