This is a great summary of our current understanding of curiosity and the important role it plays in individual lives and the society built by those individuals. I see in some of the other reviews that it is dismissed as popular fluff. In a sense, that's fair, since it's a summary, and Leslie doesn't add any new scientific evidence to the academic field of curiosity and learning. But those who do define the field have produced works that are a lot less fun to read than this -- they're not popular for a reason. Good, simple communication is not just fluff. I would highly recommend this book to my friends and students, something I can't say of the more scientific works on the subject.
I appreciated the focused organization of the book. Leslie wrote a table of contents with chapter headings that are clear and honest (that's really what that chapter is about!) and stuck to his point in each one. He covers how curiosity works, how it gets started (early childhood stuff), and how it is encouraged (or not, or should be) in schools, and how it is sustained in adults. He also speaks convincingly of its importance in an age of information. Machines will never learn to be curious, and therefore will not be creative.
In short, I really enjoyed this book, even if it didn't introduce me to a lot of new information. It is well written and has a chatty style, and the organization and simple analysis, in and of itself, helped me to see slightly different angles of the subject than I had before. But mostly I'm excited that there is finally a great little book about curiosity that I can recommend to others, even if they're not up on the field as a science.