The Aryan Jesus (Princeton, 2008), in part the story of how the German churches, both Protestant and Catholic - and their theologians - actively courted and collaborated with the Nazi regime like fawning lapdogs. And yes, propaganda to the contrary notwithstanding, that applies in part to the "Confessing Church" as well.
The cover picture in itself is incredibly powerful, showing the altar of a church in Cologne, 1935, draped with the swastika. Heschel tells a grim tale of self-delusion and fantasy dressed up in agenda-driven scholarship, a horrendous indictment on the Christian churches.
When Heschel then comments on the just passed papal visit to Britain, I for one am willing to sit bolt upright and pay close attention.
Here it is.