Mother Night
Mother Night is a novel first published in 1961 and written by the American author Kurt Vonnegut Jr.It is the story of a Howard W. Campbell Jr., an American Nazi propagandist and US counter spy during WW2. Howard is eventually held for trial in Israel, and after the war lives in isolation in New York. Much of the discussion in the book centres on Howard having done his job as a radio broadcaster for the Nazi's a little too well.
The moral of this story, as pointed out by Vonnegut himself in the introduction, is also the source of his most famous quote: "We are what we pretend to be, so we must be careful about what we pretend to be."
It is a compassionate novel (for Vonnegut), while retaining some of his normal satirical flavor.
Mother Night was made into a film in 1996, starring Nick Nolte and directed by Keith Gordon.