On November 21, 1961, Michael C. Rockefeller, the twenty-three-year-old son of New York governor Nelson Rockefeller, vanished off the coast of southwest New Guinea when his boat capsized. He was on a collecting expedition for the Museum of Primitive Art, and his partner--who stayed with the boat and was later rescued--shared Michael's final words as he swam for help: "I think I can make it."

Despite exhaustive searches, no trace of Michael was ever found. Soon after his disappearance, rumors surfaced that he'd made it to shore, where he was then killed and eaten by the local Asmat--a...