Here is what some reviewers have said about the book:

As with the best science writing, this book is engaging, accessible, and filled with vividly drawn characters.
Barbara Genco in School Library Journal

E=mc2 is not an incomprehensible abstraction, Bodanis assures us. It is as tangible as sunshine and as easy to understand as a recipe for chocolate cake. Energy equals mass times the speed of light squared. The terms of the equation are fairly straightforward and its math is at the level of junior high algebra. The difficulty lies in grasping the bold concept embodied by those five symbols. In E=mc2, Bodanis illuminates a path toward comprehension, and makes the journey as entertaining as it is enlightening.
L.D. Meagher on CNN Interactive

Bodanis' work has drama, suspense, good pacing and even a love story or two. From the placid obscurity of Einstein's early career to the war-time race to develop the atomic bomb, climaxing in Hiroshima's destruction, E=mc2 shows how this famous equation changed the world irrevocably. It's a highly readable book about a complex topic, and you won't need a science degree to understand and enjoy it.
Brett Peruzzi on the Book Page