Robert D. Mare, PhD is a Research Professor and Distinguished Professor Emeritus of Sociology at the University of California, Los Angeles. He is the 2010 President of the Population Association of America. He is widely known for his contributions to social demography in five major areas: models of educational stratification; marriage markets and assortative mating; statistical methods; neighborhood change; and population models of stratification. His research on educational transitions spawned an entire field of research on educational transitions and he is one of the leading specialists in educational stratification in the world today. Mare’s work on assortative mating has shown, among other things, that educational homogamy has increased over time and that, within cohorts, homogamy increases with age as a consequence of divorces, remarriages, and educational upgrading. Mare uses statistical methods, not for their own sake, but as a tool to think more clearly about social phenomena and to find better ways to address substantive research questions. Mare has been a Fellow of the Center for Advanced Studies in Behavioral and Social Sciences, a Guggenheim Fellow and a recipient of the American Sociological Association’s Lazarsfeld Memorial Award. He has also served in a number posts at the University of Wisconsin, UCLA, and PAA and as editor of the journal Demography.