"In God's Underground" by Richard Wurmbrand has so many interesting subjects.
It makes me think that I need to know the Bible more and know more about the faith that I profess. For instance, he was in solitary confinement for three years, and what got him through was thinking about God and remembering Scripture. I'm afraid I would be at a loss if I didn't have a Bible there to read.
Wurmbrand was also able to get through to a lot of people, because he could argue theology. He knew Scripture but he also knew about Karl Marx, Martin Luther and others that he could quote to prove his arguments.
In one passage, he talks about having tuberculosis and being sick enough that doctors told him that he would survive two weeks. He lived 30 months in what was deemed the "death room" before becoming well.
He said, "Scores of men died, and their places were taken by others in the 30 months I lay in this room. But here is a remarkable fact. No one died an atheist."
He approached the topic of atheism different than many people would. He said many people entered the death room as unbelievers, but faced with their end they turned from that "belief."
"I saw their unbelief collapse, always, in the face of death. I have heard it said, 'If a cat crosses a bridge, it doesn't mean the bridge is sound; but if a train crosses, then it surely is.' So if a man calls himself an atheist as he sits with his wife over tea and cakes, that is no proof of atheism. A true conviction must survive enormous pressure, and atheism does not."
Christianity can survive the most oppressive opposition, but, like atheism, when it's not real it doesn't survive. We all need to make sure that our Christianity is like a bridge that will support a train, not just a cat.