Let me preface this by saying that I do like Kaku as a writer — Hyperspace is still one of my favorite books (I’ve given it as a gift on 3 separate occasions), and his followup “Visions” was equally good.
This, though… I was disappointed. But only because I’ve read all of his books up until now.
The content was interesting, but I really didn’t see much that I hadn’t already seen in his previous books — it was just written in a way that assumed the reader was slightly less scientifically / physically literate, contrasted to how his previous books were.
If you’ve never read his work before, and are curious for a nice smooth survey through some rather sophisticated aspects of the physical sciences, then the book is definitely worth reading — seasoned Kaku fans will be disappointed though.