Caliban's War

Caliban's War is a 2012 science fiction novel by James S. A. Corey, the pen name of Daniel Abraham and Ty Franck, and the second book in The Expanse series. It concerns a conflict in the solar system involving Earth, Mars, the Asteroid Belt and the outer planets, and a powerful extraterrestrial biological probe.

It was preceded by Leviathan Wakes, and the third book, Abaddon's Gate, was released on 4 June 2013. One of the novellas published alongside the series, Gods of Risk, takes place directly after the events of this novel. Since the first book, the protomolecule has been assembling a vast structure on the surface of Venus, which is where the alien material has gone rather than remaining where it was found.

The novel distributes its attention across four viewpoints and locations. Holden and his crew have been keeping the peace for the Outer Planets Alliance, and agreeing to help a scientist search war-torn Ganymede for a child is what puts a private errand in the middle of an interplanetary standoff. The series was adapted for television. Ganymede is the breadbasket of the outer planets, so the slaughter of a marine platoon there is a strategic event rather than a local crime.