Books in the Long Earth series in order

1916: the Western Front. Private Percy Blakeney wakes up. 2015: Madison, Wisconsin. Cop Monica Jansson is exploring the burned-out home of a reclusive (some said mad, others dangerous) scientist when she finds a curious gadget - a box containing some wiring, a three-way switch and a...potato.

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...

2040-2045: In the years after the cataclysmic Yellowstone eruption there is massive economic dislocation as populations flee Datum Earth to myriad Long Earth worlds.