I gave this book 3 stars because it is exactly like its title: A gentle introduction to the Next Big Idea, and it is exactly what I can like but never really like. Fairly speaking, if you want to read something to have an overview about current technology, this is a decent choice, 4 stars and a half maybe. Compared to Understanding Nanotechnology of Scientific American, this book is much clearer without losing much technical insights.
Highly recommend this book if you want a quick, lightly-reading overview of nanotechnology.