A generation after the events ofThe Long Earth, mankind has spread across the new worlds opened up by Stepping. Where Joshua and Lobsang once pioneered, now fleets of airships link the stepwise Americas with trade and culture. Mankind is shaping the Long Earth but in turn the Long Earth is shaping mankind ... A new America, called Valhalla, is emerging more than a million steps from Datum Earth, with core American values restated in the plentiful environment of the Long Earth and Valhalla is growing restless under the control of the Datum government... Meanwhile the Long Earth is suffused by the song of the trolls, graceful hive-mind humanoids. But the trolls are beginning to react to humanitys thoughtless exploitation ... Joshua, now a married man, is summoned by Lobsang to deal with a gathering multiple crisis that threatens to plunge the Long Earth into a war unlike any mankind has waged before.

Author of the Discworld series, Terry Pratchett is one of the UK's most popular - and bestselling - writers. His books have sold over 65 million copies worldwide and been translated in to nearly 40 languages. Awarded an OBE in 1998 and knighted in 2009 for his services to literature, he lives in Wiltshire.

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' The Time Machine. He lives in Northumberland.