Dental anthropologists focus on the variation around a commonly shared pattern, a variation expressed by differences in tooth size and morphology. This book centers on the morphological characteristics of tooth crowns and roots that are either present or absent in any given individual and that vary in frequency among populations. These nonmetric dental traits are controlled largely by genetic factors and provide a direct link between extinct and extant populations. The book illustrates more than thirty tooth crown and root traits and reviews their biological and genetic underpinnings. From a database of more than 30,000 individuals, the geographic variation of twenty-two crown and root traits is graphically portrayed. A global analysis of tooth morphology shows both points of agreement and disagreement with comparable analyses of genetic and craniometric data. These findings are relevant to the hotly contested issue of timing and geographic context of modern human origins.