The astonishing new SF novel from multi-award winning author Stephen Baxter - a dizzying exploration of alternate universes and deep time.

The mind-blowing, time-warping science fiction epic that puts grand scientific ideas into a thrilling page-turning narrative

Fresh from his latest collaboration with Terry Pratchett on the Long Earth sequence Stephen Baxter now returns to the mysteries and challanges first hinted at in his acclaimed novel PROXIMA.

In PROXIMA we discovered ancient alien artifacts on the planet of Per Ardua - hatches that allowed us to step across light years of space as if we were stepping into another room. The universe opened up to us. Now in ULTIMA the consequences of this new freedom make themselves felt. And we discover that there are minds in the universe that are billions of years old and they have a plan for us. For some of us. But as we learn the true nature of the universe we also discover that we have countless pasts all meeting in this present and that our future is terrifyingly finite. It's time for us to fight to take back control.

This is grand scale, big idea SF of the best possible sort. It is set to build on the massive success of PROXIMA and define Stephen Baxter's work going forward.

Read what everyone is saying about Ultima:

'So much fun of a read this turned out to be. Filled with SF inventiveness, delivered in a spontaneous, unforced pace. A treat. Five stars for sure' Goodreads reviewer, ⭐ ⭐ ⭐ ⭐ ⭐

'This is one of the best books that Baxter has written to date, cleverly conflating some of his most beloved ideas, from deep time to alternate histories. Not to mention the immutability of the human spirit' Goodreads reviewer, ⭐ ⭐ ⭐ ⭐ ⭐

'I love both time travel and alternate universe stories, so the fact that Ultima was able to exceed my already-high expectations is awesome' Goodreads reviewer, ⭐ ⭐ ⭐ ⭐ ⭐

'Excellent, as usual. A combination of the historical and scientific. Fascinating' Goodreads reviewer, ⭐ ⭐ ⭐ ⭐ ⭐

'A rollercoaster of a ride across space, universes, and time, and what ultimately draws you on the most is the mystery surrounding the hatches and who built them and why' Goodreads reviewer, ⭐ ⭐ ⭐ ⭐ ⭐

'Baxter again makes mind-blowing concepts accessible with an enthralling story to explain them' Goodreads reviewer, ⭐ ⭐ ⭐ ⭐ ⭐