In the wake of an extinction-level meteor impact, a small group of human survivors manages to leave the barren Earth and establish a new home on the moon. From Tycho Base, they're able to observe the devastated planet and wait for a time when return will become possible. Finally, after millennia of waiting, the descendants of the original refugees travel back to a planet they've never known, to try to rebuild a civilisation of which they've never been a part. But after so much time, the question is not whether they can rebuild an old destroyed home, but whether they can learn to inhabit an alien new world - Earth.
Winner of the John W. Campbell Award for best novel, 2002
TheOEDcredits SF Grand Master Williamson (The Humanoids; The Legion of Time; Drago's Island; Darker Than You Think) for coining the term "terraforming" (in his 1942 novel, Seetee Ship) to describe an alien world altered for human habitation. With the terraforming of Earth itself, the original concept now gets an oblique and awesome twist well over half a century later. Williamson's skill at speculative fiction is once again evident in this far-future saga of mankind's destiny, previously serialized in Analog and Science Fiction Age. Driven by the potential threat of asteroids, wealthy eccentric Calvin DeFort set up a robot-run moonbase, Tycho Station, with frozen tissue specimens of plant and animal life. The value of this "safety net for Earth" becomes evident when a devastating asteroid impact brings a new Ice Age. Eventually, clones of the few survivors study their past history and train to reseed the planet by sowing the scarred surface with life-bombs. Bringing the gift of life, biologist Tanya and pilot Pepe are rewarded with death in the hostile environment. A million years later, more clones continue the mission. Earth evolves. A new civilization arises and crumbles. Generations of clones march through the millennia, continuing to examine the planet's riddles and ever-changing enigmas, even as Earth is on the ascendant. Throughout, poetic undercurrents permeate this masterful work by a superb chronicler of the cosmic.