The burden of Mrs. Irwin's study in pre-Colombian history is that the ""solationist"" theory of the peopling of this continent (and its sister) is less credible than the ""diffusionist"". The first theory holds that similar myths, artifacts and vegetables discovered in this hemisphere and also in Polynesia and other places were solidified, made or grown independently by peoples in total cultural isolation. The ""diffusionists"" hold that there is much evidence to support the idea that a certain people or peoples crossed the Atlantic a millenium or two before columbus. Mrs. Irwin delves into the nautical backgrounds of ancient maritime nations to determine the how and why of any such voyages. Two of the more fascinating riddles she asks: how did the beards get on to pre-Colombian statues (Indians everywhere are beardless), and where did the Indian legends of the bearded Fair Gods white men) come from? How is it possible that several hundred Roman coins, the latest stamped 350 A.D., could be dug up in Venezuela a few years ago?--her reply: transoceanic contacts. The conqueror Cortez himself discovered evidence of ancient attempts to Christianize the Aztecs. This is an absorbing, authoritative work of popular scholarship by an amateur archeologist. Well illustrated and well worth reading, although you turn up many a ""chances are"" and ""it may have been"" by barely touching your spade to the page.