Used. Mass Market Paperback. Gregory Benford’s *Great Sky River* drops us hard into a hard-sci-fi crucible where humanity is reduced to hunted scavengers scraping by on a frigid world dominated by merciless machine overlords. When a bizarre entity reaches out from the event horizon of a black hole to address a desperate father, the remnants of our starfaring species suddenly find themselves staring down a whole lot of cosmic trouble. This gritty, mercilessly mechanical space opera asks whether our fallen descendants can decode a truly alien message before their silicon stalkers finally stamp us out. It is stellar worldbuilding that treats artificial intelligence not as a quirky sidekick, but as an existential mechanical menace worthy of your undivided attention. Come grab a copy before the neighborhood nanobots beat you to it.