This book follows the story of the life of the famous equation, describing a little about its ancestors (each of e, =, m, c and squared), how Einstein put them all together, and the life the result took on after he had.
It describes a lot about the research done during wartime, explaining how the bombs work and some of the people who were working on it. I was a little disappointed by the lack of discussion of either power generation or particle accelerators, both of which seem, to me, at least somewhat relevant. And he managed to avoid much in the way of talking about either Dr Strangelove or his inspiration John Von Neumann (who only appears briefly).
The writing is easy going, not too technical, its about the life of the participants not the physics itself, but its nice to have a context for some of it.
Who should read this book: non-physicists who are interested in how discoveries travel through the scientific community, anyone who would like more context for how the atom bomb came to be developed.