To get permission to catalog the plant life of Pohnpei, a tiny island in Micronesia, Michael Balick lived among the local people for months, trying to explain how such an inventory could preserve the island's rapidly disappearing culture.

After two years, the King of Nett, a small kingdom of 5,000 people, finally called the ethnobotanist for a meeting. On a rocky outcrop overlooking the waters of the Pacific, the king rendered his decision: "I had a dream that a foreigner came in on the wings of a bird and landed on our island...