The Long Earth is a space thriller mystery book written by Terry Pratchett and Stephen Baxter. It explores a world where multiple parallel Earths exist, each slightly different from the others. The story follows Joshua Valiente, a man who can traverse these parallel Earths, as he embarks on a journey to uncover the secrets of the Long Earth. Along the way, he encounters strange creatures, meets fellow explorers, and unravels the mystery of the origins of the Long Earth. With its imaginative premise, engaging characters, and thrilling plot, The Long Earth is a must-read for fans of space thrillers and alternate realities.