Zero: The Biography of a Dangerous Idea by Charles Seife
This is the book that kindled my interest in Nothing. Before that, I'd never really contemplating the subject, but once my eyes were open there was no going back.
The book is concerned, as you might guess, with the number zero, its history and use. Seife is a terrific author, and the book is a very easy, fun read; he really emphasizes the cultural aspects of zero alongside the math. It's a great introduction to the subject.
The Book of Nothing by John Barrow
This book is more expansive than Zero, and expands more into other aspects of Nothing like physics and art. John Barrow is one of my favorite science writers, and this book is what turned me on to him.
The Hole in the Universe by K.C. Cole
This book mainly deals with physics, but also gets into psychology and cognitive science and revels in the linguistic games nothing plays.
The Nothing That Is: A Natural History of Zero by Robert Kaplan
Another book tracing the origins and usage of zero, it is not as interesting or wide-ranging as Seife's book. It's much more focused on the mathematics.
The Void & Nothing: A Very Short Introduction by Frank Close
The most recent full treatments on Nothing.
Nothingness: The Science of Empty Space by Henning Genz
A good overview of Nothing.
Patterns in the Void: Why Nothing Is Important by Sten Odenwald
Probably my favorite book about Nothing, because it uses Odenwald's own life and relationship with Nothing to illustrate the concepts. It's just a really enjoyable, well-written book.
Signifying Nothing: The Semiotics of Zero by Brian Rotman
This is a book I don't have and have only really ever flipped through in the library, but for completeness sake I list it here. It's not on a subject I find terribly interesting, but perhaps some day I'll look at it again and find I was wrong, or maybe you'll just be more interested.
You Don't Have To Be Buddhist To Know Nothing by Joan Konner (ed.)
The latest addition to my library of nothing, this is a compendium of quotes from a wide range of notables -- from artists to poets to philosophers to scientists and beyond -- about Nothing. Several of the quotes the previous post are garnered from it. It is also the impetus for this series.