The East Coast of North America is a wondrous, intriguing, yet threatened coastline. It zigs and zags for more than 5,500 miles and assumes a multifaceted, jigsaw shape from the Arctic Circle and Greenland across the Canadian Maritimes, then southward into Maine, Cape Cod, New York Harbor, the Delaware and Chesapeake Bays, along the Outer Banks to Charleston Harbor and on to Cape Canaveral. It ends at the Dry Tortugas on the western tip of the Florida...