of the realm of current physics that nobody believes it. The space tunnels also lead to the discovery of the Fallers, an alien race who refused to establish communications and immediately launched a war, which they are winning. No Faller has been captured alive—they prefer to suicide or kamikaze—but forensic examination of corpses indicate they evolved separately from humans, instead of being seeded by the progenitors. Like humanity, they were not an interstellar race until the discovery of a space tunnel in their system, though they have been closing the gap quickly. Unlike humans, they did not discover the tunnel independently; it was, in fact, a Terran craft emerging into their home system that catapulted them onto the interstellar stage. The Probability novels shares two technological quirks with another of Nancy Kress' trilogies, the Beggars trilogy: in both stories, use of both genetic modification and behavior-regulating neuropharmacological drugs is commonplace. "Genemods" are applied in vitro, whereas those who adhere to the "Discipline" administer "neuropharms" daily to control their neurotransmitter balances, in a mix that can be altered depending on the activities of one's day and the mood one hopes to approach it with. Plot synopsis While the human race struggles at war with the Fallers, an advanced alien race, an artifact is discovered which might be the key to a lost science, be a weapon itself, or a doomsday device. Reception Both Kirkus Reviews and Publishers Weekly gave the book favorable reviews. References 2001 American novels 2001 science fiction novels American science fiction novels Works by Nancy Kress