I initially read this in German many years ago, and fell in love with it then. I've always wanted to own the English version so that I could share it with others, and figured I would read it first.
The tale mirrors Oppenheimer a bit, or any of the other inventors of the terrible weapons that have come to pass and said to themselves 'I've created something so horrific, no one would ever use it.'
The Physicist creates a weapon, and just as he starts to wind down his research, he realizes what could happen if someone got a hold of this. What does he do? He pretends he is crazier than a peach orchard sow, gets sent to an Asylum and lives out his days, keeping a close eye on his discovery and pretending that King Solomon is talking to him.
Hijinks of the dark comedy variety ensue when two nations try to get a hold of his weapon design by sending a spy each to the Asylum, and as the body count and the blood pressure of the local police force starts to go up, it's a shocking twist at the end that makes this dark tale so woefully entertaining.