This report is about people living on an edge, an unstable edge of sand arcing into the North Atlantic at the tip of Cape Cod, Massachusetts. They are dune dwellers, self-reliant mavericks choosing to live seasonally in fragile shacks perched on a ridge of barrier dunes above the sea. Here in winter, the empty shacks are exposed to battering northeast storms from the open ocean. From spring through fall when the shacks are used, they are bathed with reflected light from unrestricted horizons. The shacks float on what some dune dwellers call a "liquid earth," dunes that move, an unstable landscape of sand, wet berry bogs, thorny heaths, and stunted patches of pitch pine and oak. For generations the special qualities at the cape's farthest end have drawn fishers, artists, writers, and authentic eccentrics, forming into distinctive communities and establishing roots. It's a wondrous edge, the dune dwellers assert, offering solitude, new vistas, and creative energy. It's why they've lived there in simple shacks for generations, to be intimately connected to it, purposively exposed on the outer edge of the continent.