[The] daring and dramatic journey [of the Kon-Tiki and her six crewmen] demonstrated beyond any doubt that the pre-European inhabitants of South America could have reached Polynesia.

The possibility is one thing, the probability another. In ["American Indians in the Pacific: The Theory Behind the Kon-Tiki Expedition"], Mr. Heyerdahl presents his arguments for the reality of such migrations. His thesis, to state it briefly, is that the earlier Polynesians came from Peru via Easter Island, and that the later migrants came from the northwest coast of North America, traditional home of the totem-pole Indians, via the Hawaiian Islands….

To support this thesis, Mr. Heyerdahl has assembled an impressive array of evidence and arguments, covering a vast bibliography and many fields of knowledge. He deals with the ethnography of Oceania and the Northwest Coast, geography, ocean currents, botany, archeology, physical anthropology and linguistics. No author could have equal competence...