An explorer of that most wondrous of islands, the human brain, writes D.M. Thomas in The New York Times Book Review, Oliver Sacks also loves the oceanic kind of islands. Both kinds figure movingly in this book--part travelogue, part autobiography, part medical mystery story--in which Sacks's journeys to a tiny Pacific atoll and the island of Guam become explorations of the meaning of islands, the genesis of disease, the wonders of botany, the nature of deep geological time, and the complexities of being human.