Take a story's temperature by studying its tone. Is it hopeful? Cynical? Snarky? Playful?
Clinical yet Affectionate
You can tell that even though he tries to remain clinically detached in order to preserve the historical accuracy of his book, Sheinkin really likes some of the people that he writes about, and he really loves history. For these reasons, he's taken great care to write Bomb like a history text, but with all the cool stories that are normally omitted from your typical textbook. For example:
The United States cut off oil exports to Japan. This left Japan—a nation with few natural resources—with barely enough fuel to survive another year. President Roosevelt hoped Japanese leaders would be convinced to stop their armies from advancing further. Instead, Japan became even more determined to conquer new territory, new sources of raw materials—even if this meant taking on the United States. (Rapid Rupture.(5)13).
See? That paragraph is definitely something you'd have to remember for a test on World War II timelines or something. But then, because Sheinkin has such a passion for the subject, little hints of tender affection seep into the narrative. It's like Sheinkin is a teacher calling on his favorite student while trying to hide the fact that he does, in fact, have a favorite student. No matter how stern he tries to keep his voice, you can tell he really likes his subjects:
Haukelid had dark wavy hair and a broad, muscular body toughened by years of hiking and skiing. When the Germans conquered Norway in 1940, Haukelid and a few friends had refused to admit defeat. They strapped guns to their backs and skied deep into the roadless forests and mountains. "There was only one thought in our heads," he later said. "Hitler and his gang should be thrown back into the sea." (Norway Connection.(6).2)
Can't you see Sheinkin grinning as he's tapping away at the keyboard? Like he's saying to himself, "Yeah, Haukelid was cool, guys. He was all muscle-y and brave. Join me in reveling at how awesome this dude was." It seems Sheinkin just can't help himself.