The Long Utopia (Long Earth, 4)Their trademark world building and questions of morality remain intact . . . The explosive cliffhanger endingalso now something of a trademarkpromises one final return to the series. Booklist The fourth novel in Terry Pratchett and Stephen Baxters bestselling series, which io9 calls a brilliant science fiction collaboration. 2045 2059. Human society continues to evolve on Datum Earth, its battered and weary origin planet, as the spread of humanity