The Long Utopia

2045-2059. After the cataclysmic upheavals of Step Day and the Yellowstone eruption humanity is spreading further into the Long Earth, and society, on a battered Datum Earth and beyond, continues to evolve.
Now an elderly and cantankerous AI, Lobsang lives in disguise with Agnes in an exotic, far-distant world. He's convinced they're leading a normal life in New Springfield - they even adopt a child - but it seems they have been guided there for a reason. As rumours of strange sightings and hauntings proliferate, it becomes clear that something is very awry with this particular world.
Millions of steps away, Joshua is on a personal journey of discovery: learning about the father he never knew and a secret family history. But then he receives a summons from New Springfield. Lobsang now understands the enormity of what's taking place beneath the surface of his earth - a threat to all the worlds of the Long Earth.
To counter this threat will require the combined efforts of humankind, machine and the super-intelligent Next. And some must make the ultimate sacrifice . . .

Terry Pratchett (Author)
Terry Pratchett was the acclaimed creator of the global bestselling Discworld series, the first of which, The Colour of Magic, was published in 1983. In all, he was the author of over fifty bestselling books which have sold over 100 million copies worldwide. His novels have been widely adapted for stage and screen, and he was the winner of multiple prizes, including the Carnegie Medal. He was awarded a knighthood for services to literature in 2009, although he always wryly maintained that his greatest service to literature was to avoid writing any.
www.terrypratchettbooks.com
Stephen Baxter (Author)
Stephen Baxter is one of the UK's most acclaimed writers of science fiction and a multi-award winner. His many books include the classic Xeelee sequence, the Time's Odyssey novels (written with Arthur C. Clarke) and Time Ships, a sequel to H. G. Wells's The Time Machine, a Doctor Who novel, The Wheel of Ice, and most recently the epic, far-future novels Proxima and Ultima. He lives in Northumberland.