I came across a good copy of this at used bookstore last week. Despite having decided years ago to NEVER read anything Holocaust-related again, I knew I couldn't pass this up: https://www.amazon.com/last-days-Maximilian-Kolbe/dp/0911782354 Haven't yet begun reading it, but will.
I read a similar book back in the 70's. I was so moved by his charity and courage. He was showing the way through diabolic horror. The light of Christ in the darkness.