The Long Earth Series
Reading Order.

A generation after the events of The Long Earth, humankind has spread across the new worlds opened up by stepping. 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.

"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. Sally, Joshua, and Lobsang are all involved in this perilous rescue work when, out of the blue, Sally is contacted by her long-vanished father and inventor of the original Stepper device, Willis Linsay. He tells her he is planning a fantastic voyage across the Long Mars and wants her to accompany him. But Sally soon learns that Willis has an ulterior motive for his request. ... Meanwhile U.S. Navy Commander Maggie Kauffman has embarked on an incredible journey of her own, leading an expedition to the outer limits of the far Long Earth. For Joshua, the crisis he faces is much closer to home. He becomes embroiled in the plight of the Next: the super-bright post-humans who are beginning to emerge from their 'long childhood' in the community called Happy Landings, located deep in the Long Earth. Ignorance and fear have caused 'normal' human society to turn against the Next. A dramatic showdown seems inevitable"--

The fourth novel in Terry Pratchett and Stephen Baxter’s internationally bestselling “Long Earth” series, hailed as “a brilliant science fiction collaboration . . . a love letter to all Pratchett fans, readers, and lovers of wonder everywhere” (Io9). 2045-2059. Human society continues to evolve on Datum Earth, its battered and weary origin planet, as the spread of humanity progresses throughout the many Earths beyond. Lobsang, now an elderly and complex AI, suffers a breakdown, and disguised as a human attempts to live a “normal” life on one of the millions of Long Earth worlds. His old friend, Joshua, now in his fifties, searches for his father and discovers a heretofore unknown family history. And the super-intelligent post-humans known as “the Next” continue to adapt to life among “lesser” humans. But an alarming new challenge looms. An alien planet has somehow become “entangled” with one of the Long Earth worlds and, as Lobsang and Joshua learn, its voracious denizens intend to capture, conquer, and colonize the new universe—the Long Earth—they have inadvertently discovered. World-building, the intersection of universes, the coexistence of diverse species, and the cosmic meaning of the Long Earth itself are among the mind-expanding themes explored in this exciting new installment of Terry Pratchett and Stephen Baxter's extraordinary Long Earth series. The complete list of books in the Long Earth series include: The Long Earth The Long War The Long Mars The Long Utopia The Long Cosmos

The Next--the hyper-intelligent post-humans--realize that the missive they received from the center of the galaxy contains instructions for kick-starting the development of an immense artificial intelligence knows as The Machine. But to build this computer the size of an Earth continent, they must obtain help from the more populous and still industrious worlds of mankind.