Most people claim Slaughterhouse Five or Breakfast of Champions as his greatest, but I must say, Mother Night Iput right up there. The plot, loaded through and through with flashbacks to the main character's past life as a secret agent for the American Government while working as "the last true American" Hanes Nazi propaganda machine, he's hunted down by neo-Nazi idol-worshipers, communist Spies, and to Israeli government desperate to put him on trial for his crimes against humanity. It is an eye-opening excercise into the human mind, loaded with Vonnegut's wit and sarcasm omnipresent. Definitely a must read for any fan Vonnegut.