A really amazingly interesting tour of the state of physics and cosmology. Kaku writes about his stuff without any mathematics, so it should be accessible to anyone with a layperson's understanding of modern physics and geometry.
It's divided into three sections.
The first explains the big bang theory, standard model and relativity. It shows what these models explain and where they fail.
The second section moves on to weird stuff like wormholes, strings, extra dimensions and other universes. The development of string theory gets a lot of attention. There is some amazing stuff in here.
The final section talks about the end of the universe. It goes over different possibilities and what intelligent life might do to mitigate or escape them. There's also a discussion of the religious implications of current cosmology, based on the anthropic principle (short story: Kaku thinks the universe kind of seems likely to appear to have been designed). There's some interesting ideas in here too.
It's shaped by Kaku's own interests and research, so feels like it might be downplaying areas he isn't interested in or feels hold little promise. I'm not saying that is the case, just that it feels like it might be.
The book also feels like I need to read it again in a month or two to really get to grips with the content.
If you are interested in cosmology and the weird stuff physics has discovered recently, this is a must-read.