Much of the credit for establishing early man's rightful foothold in history goes to author-adventurer Thor Heyerdahl, who popularized his theory of the evolution of navigation and civilization in his Kon-Tiki (Pacific) and Ra (Atlantic) expeditions. This slightly repetitive and highly detailed collection of essays [Early Man and the Ocean] bolsters the Norwegian's contention that "invisible marine conveyors"—tides and currents—not only dictated the flow of ancient oceanic traffic, but also determined the diffusion of culture.

More compelling is Heyerdahl's understated, secondary theme, that historical evidence can be manipulated and perverted by scientific bias or ethnocentrism…. For the sake of simplicity, if not greed, it was quietly overlooked that European explorers were drawing on the expertise of Inca informants, Phoenician merchant colonizers, West Coast Haida Indians and other "primitives," who, generations earlier, carved routes through the same waters. (pp. 56-7)

That same narrow-mindedness gripped 19th- and 20th-century...