Stephen Baxter

"It has been 14 years since the Martians invaded England. The world has moved on, always watching the skies but content that we know how to defeat the Martian menace. Machinery looted from the abandoned capsules and war-machines has led to technological leaps forward. The Martians are vulnerable to earth germs. The Army is prepared. So when the signs of launches on Mars are seen, there seems little reason to worry. Unless you listen to one man, Walter...

Returned to the Earth of 2037 by the mysterious and powerful Firstborn, Bisesa Dutt is haunted by memories of her five years spent on the strange alternate Earth called Mir, a jigsaw-puzzle world made up of lands and people cut out of different eras of Earth's history. Why did the Firstborn create Mir? Why was Bisesa taken there and then brought back just a day after her disappearance?

The Next -- the hyper-intelligent post-humans -- realize that the missive they received from the center of the galaxy contains instructions for kick-starting the development of an immense artificial intelligence knows as The Machine. But to build this computer the size of an Earth continent, they must obtain help from the more populous and still industrious worlds of mankind.

Lobsang's pursuit of a human life, Joshua's search for his father and the adaptation efforts of "the Next" post-humans are challenged by a voracious alien race that would conquer and colonize the Long Earth. "2045-2059. Human society continues to evolve on Datum Earth, its battered and weary origin planet, as the spread of humanity progresses throughout the many Earths beyond. Lobsang, now an elderly and complex AI, suffers a breakdown, and disguised...