Just a few thoughts:
1. The bravery: In this book, Jan risks his life every day, sneaking into the Warsaw Ghetto (a space no larger than 15 blocks, filled with disease, that holds thousands of Jews) and sneaking out with one prisoner at a time. I want to think if faced with a situation like this, I would be one to be brave, but it's hard to know for sure. Anyone who survived this time (or any forms of genocide that exist today) are true heroes.
2. The number of Germans who also risked their lives by looking the other way. Jan couldn't have sneaked into the Ghetto if it weren't for a very powerful Nazi covering for him. It's a least a bit hopeful knowing they weren't all bad.
There was a marathon of Band of Brothers on the History Channel this weekend. An excellent series about Easy Company's fight throughout WWII. In one of the final episodes, the company comes across a concentration camp. It's 1945. The troops have never heard of these camps. They didn't know this was going on, even when they landed in Normandy, even when they fought in the dead of winter at Bastonge. If any of those soldiers had any doubt about why they were fighting, I think those doubts must have vanished when they saw all the dead bodies and the hundreds of starving people. It made me think of this book. At least people like Jan and Antonina saved a small percentage.