The novel “The Long Earth” by Terry Pratchett and Stephen Baxter was published for the first time in 2012. It’s the first book of The Long Earth series.

When the instructions to build a Stepper, a device that allows to move to a parallel universe, are made public on the Internet, a new frontier opens up for humanity. Anyone can do it and there seem to be infinite parallel universes where the Earth is similar but with some differences, hence the expression “Long Earth” and in none of them human beings evolved.

When human being move to a parallel universe they feel nausea but Joshua Valienté is an exception. He gets hired to participate in a an expedition to explore the Long Earth along with a truly unique companion, Lobsang, an artificial intelligence who claims to be the reincarnation of a human being.