After the Spanish Civil War he settled down in Barcelona, where he worked at a great number of jobs while writing as a background activity.

Pedrolo's name will remain forever attached to the title of his most popular work, his first attempt at the sci-fi genre, Mecanoscrit del segon origen ("Typescript of the Second Origin").

Alba, a fourteen-year-old girl, and Dídac, a black nine-year-old boy, become the two only remaining humans on Earth after they accidentally survive an alien holocaust that eradicates all mammal life on the planet.

As Alba and Dídac bravely recover from the catastrophe, they not only insist on living in a post-apocalyptic world, inhabited by myriads of corpses and deranged, psychotic survivors, but they also take up the mission of preserving human culture and repopulating the Earth.

The well-documented scientific data and the use of cultured-but-readable language are just two of the reasons for the success of this book, which has had a deep impact on Catalan culture[citation needed].