The Phantom Isles

The book is called The Compleat Necromancer, and when Ming, Orion, and Courtney read an incantation from its pages, they have no way of knowing they are about to conjure up the ghosts of an entire nation. Because the ghosts that the three friends summon aren't just any ghosts. They were captured from an island in the middle of the Indian Ocean--the Ilhas dos Fantasmas--a place where the living and the dead once coexisted peacefully. Now confined to the pages of a few dozen library books in a New England town that's thousands of miles from their home, the ghosts must rely on the children and a determined librarian to free them before they are lost forever.