The Boys from Brazil, by Ira Levin

 What a great book!

Spoilers: 

Ezra Lieberman is a Nazi hunter. Barry Kohler thinks he is too, and follows suspected Nazis to a restaurant in Sao Paolo. Unfortunately for Barry, Dr. Mengele (yes, that Mengele) is a killer of Nazi hunters. Barry's life is cut short. But not before he's contacted Lieberman and got his interest. 

Lieberman dismisses Barry's concerns at first, but hears him being killed, then feels hatred on the other end of the line, and is sure it is Mengele. Thus begins his hunt.

Mengele's plan involves the death of 90+ men, all around 65 years old, all civil servants. It slowly is revealed that each of these men has a son, around 14 years old, and a mother around 40. These boys from Brazil, all clones of Hitler (yes, that Hitler), need to experience their father dying, just like the real Hitler did. If the Fourth Reich is to rise, that is. 

The Reich doesn't rise, as Lieberman figures out Mengele's plan. Mengele also figures out Lieberman's plan. They both end up in the same house, home to one of the civil servants scheduled to die, a breeder of Dobermans. Mengele gets there first, cleverly talks the man into locking his dogs into a separate room. He kills the target, then stays to act as the man. Lieberman shows up to warn the man of his pending death and quickly figures out who's sitting in the living room with him. He gets up to let the Dobermans out of the locked room, but gets shot several times. The dogs hold Mengele in his seat and soon the boy, Hitler mini, comes home. He's really into making movies. (In the movie he's a photographer.) The boy sees through Mengele's attempts to place the blame on Lieberman and sics the dogs on the Angel of Death. Then he films the scene. He makes a handshake deal with Lieberman to not mention he (the boy) was there for Mengele's death, or he wouldn't call the ambulance for Lieberman. 

And in a final scene, the author describes another boy from Brazil, this one an artist, drawing excitedly a scene right out of Hitler's Germany. 94 possible Hitlers, perhaps 2 probables? 

Ich bin fertig mit den Spoilern ^^^.

Wife's choice for family book club and what a great pick it was. She and I watched the movie the day after I finished. Very well done with Gregory Peck and Laurence Olivier and Jeremy Black, the boy from Brazil, who played at least four of them IIRC, each with a different accent. This was his only film; I guess that was enough for him as he stuck to stage work after that. Wonderfully well done film.