The well-known zoologist/illustrator's second novel (The Helix and the Sword, 1983), an inventive, message-y, but fundamentally unsound enterprise. In the 21st century, following a short nuclear exchange, the world is polarized into East (doctrinaire Marxists) and West (military/industrial/religous democrats). Out near Uranus, a Soviet probe has encountered what might be an extrasolar artifact. Both East and West promptly launch heavily-armed interceptor ships, which soon blow each other to smithereens. Four survivors are rescued by Charon, a benevolent, superpowered, billion-year-old alien probe. In tedious detail, Charon explains his ""toolmaker koan"": all civilizations that develop technology and space travel destroy themselves in meaningless wars. So, Charon will reconstitute some aliens from its memory store, in the hope that humans and aliens can learn enough about each other to avert the coming Armageddon on Earth (how's that again?). The alien ""whileelin"" turn out to be predatory dinosaurs! (Savvy readers will realize what's going on here.) Eventually, Charon brings the survivors back to Earth, where the final nuclear war starts anyway: the whileelin, who built themselves a space habitat 65 million years ago before wiping themselves out (yes, they really are Earth dinosaurs), come back to life and threaten the human survivors of the war--so Charon must destroy them. Fascinating ideas, gloomy message-ing--along with an unworkable plot and cardboard characters in a flatly undramatic narrative. Back to the drawing board.