The Nothing That Is: A Natural History of Zero by Robert Kaplan This book is well described by its title; it is a history of the concept of zero as seen in different cultures. Robert Kaplan is a professor, and this book reads much like a lecture. To read this book, you should know algebra, and calculus would be helpful. Kaplan frequently uses phrases in other languages and expects the reader to know rudimentary latin and greek.
The biggest problem with this book is that the author is trying to reach a diverse audience. He uses terms that younger and less learned readers will not know, and he goes into detail about topics where anyone advanced enough to know what he is talking about will have already learned. Nonetheless, this book contains many interesting tidbits and anecdotes. If you do not mind skimming parts of the book, this is a good read.
Happy reading.