Roberto Bolaño’s novel The Spirit of Science Fiction will be published in English translation next year. The translation is by Natasha Wimmer (who translated 2666 and The Savage Detectives, among other Bolaño works). Bolaño began The Spirit of Science Fiction in 1984 but apparently never finished it. The novel was first published in 2016 by the Spanish publishing house Alfaguara. Based on the blurb, The Spirit of Science Fiction sounds like a prototype for The Savage Detectives (much as Woes of the True Policeman is a prototype of 2666).
Here is the blurb from the publisher, Penguin Random House—