For an overview of the setting minus the story of the Jehovah's Witnesses I recommend 'On the Road to the Wolf's Lair' by Hamerow. It dispels some of the contemporary Evangelical myths and misunderstandings of what was happening in German ecclesiastical culture and circles at the time.
The Jehovah's Witnesses demonstrated how the Church should be conducting itself. I say this to the Church's shame for the Jehovah's Witnesses do not possess the gospel.
No one ever suggested it would be easy. But as I read this I wondered if Christians had behaved this way during Vietnam or even the Iraq Wars how would they have been treated? How would faithful Christians be treated by other Evangelicals?