A LONG WALK TO WATER BEGINS AS TWO STORIES, TOLD IN ALTERNATING SECTIONS, ABOUT A GIRL IN SUDAN IN 2008 AND A BOY IN SUDAN IN 1985. THE GIRL, NYA, IS FETCHING WATER FROM A POND THAT IS TWO HOURS’ WALK FROM HER HOME: SHE MAKES TWO TRIPS TO THE POND EVERY DAY. THE BOY, SALVA...