Young Adult Literature; Quest; Historical Non-Fiction
Young Adult Literature
Even though this book could obviously appeal to readers of all ages, Sheinkin wrote it with the intention of making history a little more interesting for teen audiences. He used to write historical textbooks to pay the bills, and now he writes books so he can tell the stories his editors wouldn't let him include in those textbooks (Source)
Quest
Compared to something like Lord of the Rings, Bomb doesn't seem quite epic enough to fit into the quest genre. However, when you think about the lengths to which some people went to build the first atomic bomb—or to steal the plans for one—you have to admit that the arms race was definitely a quest of some sort. There was a distinct goal people were trying to achieve, there were bad guys making it hard to achieve that goal, and lots of people died. We'd say that qualifies, all right.
Historical Non-Fiction
This is the most fitting genre for Bomb. Basically, Sheinkin wrote a historically accurate accounting of how the atomic bomb came to be and what people did to try to steal it. Sure, there could be some wiggle-room for his interpretation of the history, but for the most part everything in the book is true. So true, in fact, that you can quote it and not fear being factually incorrect.