Every short story in this wonderfully varied collection has one thing in common: each features some alteration in history, some divergence from historical reality, which results in a world very different from the one we know today. As well as original stories specially commissioned from bestselling writers such as James Morrow, Stephen Baxter and Ken MacLeod, there are genre classics such as Kim Stanley Robinson’s story of how World War II atomic bomber the Enola Gay, having crashed on a training flight, is replaced by the Lucky Strike with profoundly different consequences.

Stories of the fall of civilisation, the destruction of the Earth and the end of the Universe itselfThe last sixty years have been full of stories of one or other possible Armageddon, whether by nuclear war, plague, cosmic catastrophe or, more recently, global warming, terrorism, genetic engineering, AIDS and other pandemics. These stories, both pre- and post-apocalyptic, describe the fall of civilization, the destruction of the entire Earth, or the end of the Universe itself. Many of the stories reflect on humankind’s infinite capacity for self-destruction, but the stories are by no means all downbeat or depressing — one key theme explores what the aftermath of a cataclysm might be and how humans strive to survive.

During his heroic first encounter with an alien race, Dick Muller was permanently altered, hideously transformed in a way that left him repulsive to the entire human race. Alone and embittered, he exiled himself to Lemnos, an abandoned planet famed for its labyrinthine horrors, both real and imagined. But now, Earth trembles on the brink of extinction, threatened by another alien species, and only Muller can rescue the planet. Men must enter the murderous maze of Lemnos, find Muller, and convince him to come back. But will the homeless alien, alone in the universe, risk his life to save his race, the race that has utterly rejected him?

When Tom Nile’s genetic structure was determined, it varied from the human norm only in one respect. Most of us have minds like sieves, through which our recollections of the past constantly leak away; but Tom came into the world incapable of forgetting anything. Such a miraculous memory is surely a blessed gift… or is it?

Piloting a space ship called for nerves of steel and an instantaneous set of reflexes; in addition there was a tougher requirement…

His choice would govern a boy’s fate—and, incidentally, Earth’s entire future.

It was in wide-eyed horror that Roy Gardner heard the news from the Chief of Security. In just sixty-seven years the Earth would be totally destroyed by the planet Lurion.That data had been compiled by the invincible computer. With unwavering faith in the machine, humans had only one thing to do—destroy Lurion first.And the man to do the job was Gardner. If he did it successfully the blood of billions would be on his hands; if he fouled up he would be the worst traitor in Terrestrial history. And not even he knew which course he would pursue when he finally learned that even the all-wise machine had not known all the right answers.