This is a classic now of a German Christian theologian who organized resistance against the National Socialists. He was arrested in 1943, and eventually executed a few days before his camp was liberated in 1945. Many of his works were smuggled out of prison. Before the war he had spent some time at a neo-pagan seminary in New York, Union Seminary. There is a brief biography by someone else at the beginning of this work which includes this gem:
"Both modern liberal theology and secular totalitarianism hold pretty much in common that the message of the Bible has to be adapted, more or less, to the requirements of a secular world. No wonder, therefore, that the process of debasing Christianity as inaugurated by liberal theology led, in the long run, to a complete perversion and falsification of the essence of Christian teaching by National Socialism."
Today, this same liberal theology is America's and Europe's established religion, more or less. The irony being that the theologians of this state religion are constantly finding National Socialists behind every challenge to their authority. Those who currently call themselves National Socialists are just as confused since they still embrace the state religion, but are somehow opposed to its consequences. This should be a good read.