I thought it was a fantastic book. I really like her style of writing, which Chad aptly describes as breezy. She tries to throw fun references in, and sometimes has some wordplay that made me laugh (but I'm a sucker for wordplay). The chapter on probability alone is worth the cost of the book, because no one really understands probability, and everyone should. It matters much more than most people seem to think.
The rest of the book is a basic overview of science (as well as why science is important), and if you're anything like me you'll know pretty much everything in it. But it's still a great read, and it never hurts to cover the basics of topics that you're not all that familiar with. She covers Physics, Evolutionary Biology, Microbiology, Chemistry, and Astrophysics, doing a good overview of each as well as explaining why each is important (which is a crucial thing to do).
Chad said that it would make a good gift for a humanities type family member, but I think that it's the kind of book anyone who isn't interested in science but hasn't given it a shot should read, or for anyone who likes science and wants a well-written, charming, and enjoyable book to enjoy for a few days (I finished it in one, but I didn't put it down). In short, I'd call this one a must-read.