The importance of the eHRAF database ultimately lies in what it can tell us about patterns of cultural variation. But we already know a great deal. The purpose of Explaining Human Culture is to briefly summarize what we have learned from cross-cultural research, or more precisely, what we think we know, and to point out some of the things we do not yet know. These summaries are only a starting point and I encourage you to use the references to delve into the theories, the measures, and the samples used in the actual research. Research usually gives rise to more questions or more research directions to pursue. We have barely begun to scratch the surface.