Neurologist Oliver Sacks is author of two previous recent best-selling books, "Awakenings" and "The Man Who Mistook His Wife for a Hat", both of which dealt with his specialty, pathologies of the human brain. In "Island of the Colorblind", Sacks takes us traveling to the islands and atolls of the Pacific: Guam, Rota, Pohnpei, and Pingelap. With him and through his perceptive eyes we are introduced to two (or three, perhaps) rare diseases. I won't spoil the story by telling you more, but I will say that one of the things I liked most about this book was that this fine writer asked plenty of questions that are not (yet) answered. One of them is whether a natural product of one or more of the genus cycad is responsible for a debilitating and often fatal disease of the peoples of those islands.