Confronted with a well-balanced society, a psychiatrist finds a new use for his skills.

"The last psychiatrist on Earth sat alone in a room. There was a knock on the door."

Galaxy (February 1956)
Atoms and Evil (1962)
Complete Stories of Robert Bloch -- V 1: Final Reckonings (1990)

The opening of this story can be seen as an homage to the Fredric Brown short story "Knock" (1948, reprinted in the Bloch edited collection "The Best of Fredric Brown"(1976)). "Knock" begins "The last man on Earth sat alone in a room. There was a knock on the door."

This story also contains two of Bloch's trademark story touches -- jaundiced asides at the psychiatric profession and puns.