This book begins rather oddly, in that it doesn't bother with scene setting or context or anything. Instead, it just starts with one of the myriad scientists who traipse through the book.

But once it gets started, the book tells the marvelously compelling story of how scientists created the most horrific weapon the world has known.

The book is primarily focused on science. Atomic science is explained pretty well, and it's fairly easy to follow along with the ins and outs of the program. The people involved are described in enough detail to get a sense of how the fitted into the vast enterprise.

The book also attempts to put the destruction itself in perspective. War is terrible, and even before Hiroshima, cities were decimated, civilian men, women, and children horribly killed. But while the author spends time to tell us some of the lowlights of war, he spends a larger section on the aftermath of Hiroshima, page after page of brutal descriptions from survivors that are difficult to read.

He also gets into the politics, shows how the decisions to drop the bomb was made and why some thought it was necessary and some thought it was not. Although he spends far less time on this than on the building of the bomb itself.

At the very end, he spends a few pages giving his take on the bomb, what it means, what should be done, and none of that is especially interesting. But he wrote a very long book on the subject so I'm sure he felt he had something to say about it. But it's just a few pages, so I'll cut him slack on that.

Overall, an excellent history of a momentous project.