The Long Earth is the first novel in a collaborative science fiction series by British authors Terry Pratchett and Stephen Baxter.

The book, set in 2030, deals primarily with the journey of 28-year-old Joshua Valienté (a natural "Stepper") and Lobsang, who claims to be a Tibetan motorcycle repairman reincarnated as an artificial intelligence.

They encounter evidence of other humanoid species (referred to as trolls and elves); of human settlers who learned their gifts early – including Sally Linsay, daughter of the inventor of the stepper, who joins them on their expedition; and of an extinct race of bipedal dinosaur descendants.

Upon reaching Earth West 101,754, they hear news that Datum Madison has been destroyed in a nuclear explosion, the result of a bomb planted by a terrorist group of humans incapable of stepping (called "phobics" in the book's terminology).

The book ends with the two of them briefly seeing the explosion site, before retreating to Earth West 1 Madison, where a backed-up instantiation of Lobsang contacts Joshua by phone.