I'm getting toward the end of Antony Beevor's The Second World War. If you only know the outlines of World War II, I would very heartily recommend it. Speaking for myself, this is the first book I've read that devotes considerable attention to the Holocaust. It's one thing to know the numbers. It is another to be faced with the methodology.
When studying a great evil, my general approach is to try to preserve my judgment but suspend my judgmentalism. In other words, I want to be able to tell you very forthrightly about the evils of, say, slavery, while at the same time telling you about the psychology of the slaveholder. And I want to do this with the full knowledge that I could have been on either side of the whip.
No historian whom I've read better handles this than Drew Gilpin-Faust. Her work on the women planters during the Civil War does not excuse anyone. When she speaks of patriarchy or white supremacy, she does it with seriousness and specificity. She manages to avoid the temptation to lump women, blacks, and poor whites into some vague activist mélange called "The People." And at the same time, Faust is able to sketch the very real societal bonds that kept these women in a cage. That humanist approach to history, as opposed to marshaling history for condemnation or the improvement of collective self-esteem, is one I have tried to emulate.