earthly paradise. Here in the Bikinian Ancestral Cemetery, with its tidy white fence and weathered graves, the 3.4-square-mile island looks exactly as Alson describes it. The sky is a deep cobalt blue; coconut palms, orange-limbed and yellow-fringed, sway in the steady trade winds. There are still breadfruit trees and pandanus trees and flame trees with brilliant red blossoms. Two hundred yards to the north, a coral reef meets the full, transparent blue violence of the Pacific. There is just one problem, though you could stare at this palm grove for a lifetime and never see it. The soil under our feet, whitish gray in color with flecks of coral, contains a radioactive isotope called cesium 137. In high enough doses, it can burn you and kill you quickly; at lower levels, it just takes longer to do the job, eventually causing cancer. The soil itself is not dangerous to touch. The danger lies in the plant life that takes it in, and in the animal life, like the huge coconut crabs that live on the island and eat the plants. The cesium 137 is fallout, a word introduced to the world during the systematic detonation, from 1946 to 1958, of 23 nuclear weapons by the U.S. army on Bikini Atoll. Over the course of a nuclear exile that has lasted 66 years, the Bikinian people have been relocated five times. They have nearly starved to death. They have seen their way of life vanish. They have watched as nuclear scientists