The Long Tomorrow is a post-apocalyptic science fiction novel by American writer Leigh Brackett, originally published by Doubleday & Company, Inc in 1955.

In the aftermath of a devastating nuclear war, Americans have come to blame technology for the disaster, and far from seeking to recover what was destroyed, are actively opposed to any such attempt.

Against their fathers' wishes, the boys attend a preaching where a trader named Soames is stoned to death for his apparent involvement with a forbidden bastion of technology known as Bartorstown.

Len's grandmother, a little girl at the time of the destruction, sparks his interest in the technological past with her stories of big, brightly lit cities and little boxes with moving pictures.

Subsequently, Esau and Len become determined to find their way to the fabled Bartorstown and leave Piper's Run in search of it, following broken dialogue heard over the radio towards a river.

The boys make their way to a town called Refuge, living with Judge Taylor and his family and working for a warehouse owner, Mike Dulinsky.

He rallies the Refuge residents, who initially pledge their support, but Judge Taylor warns Len and Dulinsky of the consequences and that he would go to the state authority.

The town's leaders seek to use the childlike vision that Len and Esau had of Bartorstown to inspire the workers, who have been working for a long time without an end in sight.

The scientists of Bartorstown have been working on a long-term project with an artificial intelligence, Clementine, aimed at creating a forcefield that would eradicate the splitting of atoms, preventing future misuse of nuclear technology.

Len mentally prepares for himself to die, thinking of Soames and Dulinsky and the disillusioned Bartorstown scientists and acknowledging that change would come around eventually, even if he as an individual passed on.

Damon Knight wrote of the novel:[1] Unhappily, as the story progresses, it seems more and more to support Koestler's assertion that literature and science fiction cancel each other out.