The third novel in the Nebula Award–winning author's classic series: “A challenging, pacesetting work of hard science fiction that should not be missed” (Los Angeles Times).
Nearly 100,000 years after first contact with the machines that dominate the universe, a few hundred humans survive. Trapped on Snowglade, a barren world near the center of the galaxy, people like Killeen of Family Bishop and his child Toby are primitive scavengers, homeless and hunted by the ruling “mechs.”
Then suddenly, a strange cosmic entity—neither organic nor cybernetic nor living matter—reaches out from a black hole to speak with Killeen. But can this fallen descendant of starfarers understand this alien being in time . . . and seize the only chance to save his family and mankind from final annihilation?