Nikolai Botev holds a PhD and MA in Demography from the University of Pennsylvania, USA and a degree in Labor Economics from the Higher Institute of Economics in Sofia, Bulgaria. He started his career in academia before moving on to work for the United Nations – initially as a research demographer with the UN Economic Commission for Europe (UNECE) and then in various positions of increasing responsibility with UNECE and UNFPA (the United Nations Population Fund). Among other things he has managed a project which resulted in a collection of internationally comparable census microdata samples for a number of European countries, and was Director of UNFPA’s office for Central Asia. His interests are in population and public policy, intermarriage and inter-group relations, population ageing and its social and economic implications, as well as historical demography and the theory of the demographic transition. He has published in journals like American Sociological Review, Population and Development Review, Population Studies, European Journal of Ageing, and have given lectures and talks in academic institutions on several continents.