The Long War: 2 (Long Earth) - Tapa blanda

The Long War by Terry Pratchett and Stephen Baxter follows the adventures and travails of heroes Joshua Valiente and Lobsang in an exciting continuation of the extraordinary science fiction journey begun in their New York Times bestseller The Long Earth.
 
A generation after the events of The Long Earth, humankind has spread across the new worlds opened up by “stepping.” A new “America”—Valhalla—is emerging more than a million steps from Datum—our Earth. Thanks to a bountiful environment, the Valhallan society mirrors the core values and behaviors of colonial America. And Valhalla is growing restless under the controlling long arm of the Datum government.
 
Soon Joshua, now a married man, is summoned by Lobsang to deal with a building crisis that threatens to plunge the Long Earth into a war unlike any humankind has waged before.

War has come to the Long Earth. . . .

Humankind has spread across the new worlds opened by explorers Joshua and Lobsang a mere decade ago. Now "civilization" flourishes, and airships link the multiple Earths. A new America christening itself "Valhalla" has emerged more than a million steps from the original Datum Earth. Like the American revolutionaries of old, the Valhallans resent being controlled from afar. And in the wake of humankind's advance, the trolls—graceful, hive-mind humanoids whose song has suffused the Long Earth—are beginning to fall silent . . . and disappear.

Joshua, now married and a father, is summoned by Lobsang. It seems he alone can confront the perfect storm of crises that could plunge all of the Long Earth into war—a war unlike any that has come before.