Judas Unchained

Judas Unchained is a science fiction novel by the British writer Peter F. Hamilton, published in 2005 and the second half of the story begun in Pandora's Star.

Its setting is the Intersolar Commonwealth, a human civilisation spread across the stars of the twenty-fourth century and confident of its own stability. That confidence ends when the Commonwealth sends a ship to examine the mystery of a star that has disappeared, and the expedition releases a hostile alien species that immediately strikes at the people who freed it. The invaders have an unsettling talent for taking on human shape, and the book works through what that means for a society held together by instantaneous travel and information: nobody can be certain who is standing next to them, and the institutions that are supposed to defend the Commonwealth are also the ones with the most to hide. The war is fought out across colonies, corporate interests and the armed forces, with a large cast whose decisions keep colliding.

Hamilton writes large-scale space opera, and this duology is among the longest and most densely populated of his future histories.