E = mc2: A Biography of the World's Most Famous Equation - David Bodanis
I listened to part of this on CD (unabridged) and read the rest of it when the book was available at the library. It's true: E=mc2 is the world's most famous equation. It's what automatically comes to mind when somebody mentions Einstein. Yet, aside from what the various letters stand for, a lot of people really don't understand what the big deal is. That's what Bodanis addresses in his book: with a mixture of historical anecdotes and scientific explanations, he creates what he calls a "biography" of the equation. Instead of following Einstein's life, he brings in all the other people who got involved with the equation and its consequences—up to the atomic bomb, and then out to the processes that keep the stars burning. He even has a chapter apiece on each of the symbols in the equation (including the "=" sign).
I've never been much of a history buff, but this book was enjoyable to read, both entertaining and educational. Granted, it's not what you'd really call a history book, either, but Bodanis places many of the events related to the equation into historical context, and gives some ideas about how various people might have been spurred to think the way they did. At the back of the book is a hefty appendix, with brief biographical notes on the lives of major characters outside of their involvement with E=mc2.
Some of the events, particularly surrounding the race for the atomic bomb, I remember learning about in a History and Science course in college. Many of the bits and pieces of the science are things that I've learned about before as well. This book did a wonderful job of showing the thread that ties these seemingly disparate events together.