Bomb: The Race to Build—and Steal—the World's Most Dangerous Weapon (Steve Sheinkin)

Captivating story of the race to build the atomic bomb. Told in a way that works for kids. The story is quite complicated but very captivating for the right reader. Lots of spies, intrigue, betrayal, secrets and more.

Goodreads summary:

In December of 1938, a chemist in a German laboratory made a shocking discovery: When placed next to radioactive material, a Uranium atom split in two. That simple discovery launched a scientific race that spanned 3 continents. In Great Britain and the United States, Soviet spies worked their way into the scientific community; in Norway, a commando force slipped behind enemy lines to attack German heavy-water manufacturing; and deep in the desert, one brilliant group of scientists was hidden away at a remote site at Los Alamos. This is the story of the plotting, the risk-taking, the deceit, and genius that created the world's most formidable weapon. This is the story of the atomic bomb.

Bomb is a 2012 National Book Awards finalist for Young People's Literature. 
Bomb is a 2012 Washington Post Best Kids Books of the Year title.

Bomb is a 2013 Newbery Honor book.