was launched in the 1930s, developed institutionally in the United States and France after 1945, and rapidly extended to many other countries. As a scientific discipline, it is among the most recent, though it now has a history to recount. In over half a century, the discipline has developed, both in terms of its themes and instruments of research and in its teaching, following different pathways and advancing at different speeds from continent to continent and country to country. What stage has the science of demography reached today? What is its place in social sciences research and teaching? Has it reached a turning point? What of its scientific visibility and its social and political utility? What of its future? Are we moving towards one or several forms of demography?These general questions, both wide-ranging and complex, will be addressed as I examine what I consider to be the discipline's assets and strengths, its weaknesses and constraints (variable from one region to another) and a certain number of short- and medium-term risks and imperatives. 1 will end with a few suggestions. These questions are not new ones, or indeed specific to our own discipline, but they are worthy of particular attention at this time.The discussion is based on the findings of recent seminars and publications devoted to the history, current situation and future of demography(1), analysis of the content of major conferences, the findings of working groups (such as the IUSSP group on teaching from 1997 to 2002), and recent major surveys of demographers(2) and research institutions around the world(3). It includes my own personal experience as a professor in a European university institute of demography, and as a researcher working mainly on population questions in countries of the South. The point of view will therefore be neither comprehensive nor totally unbiased.I. is no longer a slow-flowing river: a rapid historical overviewBarely thirty or forty years ago, demography was a clearly delimited discipline, precisely defined in terms of its topics and methodology. Its essential objects were structures by age, sex and marital status, fertility, mortality and internal migration; its basic tools were standard demographic analysis and elementary statistics; most of its data came from administrative information systems (civil records, censuses, the occasional register)(4). We measured phenomena and growth rates, described levels and trends, we projected (as best we could), and worked mainly at aggregate level. This can be seen in many of the definitions of demography that were given in those days. Here are just a few examples(5).Hauser and Duncan (1959): Demography is the study of the size, territorial distribution, and composition of population, changes therein, and the components of such changes.Kirk (1949): Demography is the quantitative study of human populations. Its central concerns are the measurement and discovery of uniformities in the basic processes of human birth, death, population movement and population growth.Bogue (1969): Demography is the empirical, statistical and mathematical study of human populations.United Nations Multilingual Demographic Dictionary (1958): Demography is the scientific study of human populations primarily with respect to their size, their structure and their development; it takes into account the quantitative aspects of their general characteristics.During the 1970s and 1980s, demography rapidly became more international as teaching and research centres were created on every continent and new schools of thought emerged'6'. National and international funding increased, in both North and South, with a clear priority given to fertility. Surveys became the preferred data collection method almost everywhere, especially in developing countries(7) . At the same time, computer technology developed rapidly and considerable progress was made in analysis (biographical approaches, models, indirect methods, etc. …