With its multiple meanings and conflicting connotations, the term “evolution” has been associated with controversy for over two centuries. Much of this dispute has concerned the relationship between the social sciences and biology. While in the nineteenth century this relationship was close, there was a dramatic parting of the ways in the twentieth century, when words like “evolution” were used less frequently. But in recent decades, evolutionary thinking in biology has had a greater impact on the social sciences. Links include the possibility that social and biological evolution might share some abstract common principles, despite the big differences between social and biological phenomena in detailed terms. In addition, empirical and theoretical studies have revealed important interactions between genetic and cultural evolution.