Reconstruction of human history by genetic data is a kind of exercise whose value is being increasingly challenged by methods and evidence from other disciplines. When I submit the methods and the results our genetic studies can provide to an audience of nonbiologists, for example, scholars of history or scholars of linguistics, the most frequent question I am asked is, "What are our studies going to gain from your studies?" In other words, how could one discipline benefit from the results of another? In the following review, I try to give some answers to this question. In a study by Cavalli-Sforza, Piazza, Menozzi, and Mountain (1988), the spread of anatomically modem man was reconstructed on the basis of genetic, archaeological, and linguistic evidence: The main message was that the three sciences reflect a common, underlying history, the history of our past still frozen in the genes of modem populations. What can be considered something more than a suggestion requires us to dig deeper into the history of populations. As a geneticist, I introduced the expression genetic histories (Piazza, Cappello, Olivetti, & Rendine, 1988b) to point out the historical interpretation of genetic data collected from extant populations, the methodological approach
based on the assumption that, if we find many genes today showing the same geographical frequency patterns, this may be due to the noncoincidental history of our species. Because biological evolution cannot be tested by reproducible experiments as in the so-called exact sciences, our effort has been directed to find support from fossil data or from such "cultural fossils" as lexical substrata, toponyms, and so forth, left exposed by languages in their process of change.