Among the latest bestsellers at the Nichols Library: Camino Island by John Grisham gives his crusading attorneys a rest while he spins a tale about a theft of rare books;     The Identicals by Elin Hilderbrand is about twin sisters Tabitha and Harper, who are so estranged, they even summer on separate islands (Tabitha with mum on Nantucket and Harper and Harper on the Vineyard with poppy); and Dragon Teeth, a posthumously discovered story by the late Michael Crichton, set in the 1800s about a callow young man who takes a bet to join a search for dinosaur bones led by rival paleontologists.