In the Presence of Mine Enemies
A work by Harry Turtledove, originally a short story that was then lengthened into a novel. Its concept focuses on the idea of Jews still living in the heart of the Third Reich as late as 2010, kept secret by a cell system including those who work on the Reich's computer records, and their balance between fear of discovery and desire to preserve their cultural and religious traditions.
The short story original was praised for its poignancy, but the novel was criticised on a number of grounds: the large number of bridge scenes, the implausible alternate history (America is conquered in 1970 by the Nazis virtually without a fight) and the excessive analogous history of the long story, which re-sets the 1991 fall of the Soviet Union in Berlin without any comparable triggers.