This is the latest report on what demographers and scientists in related disciplines think and assume today about the future of human reproduction, longevity, and migration. A quick look at some major errors in past population projections demonstrates that the problem was not with the technical instruments of projection but with the inability to anticipate major changes in human behavior and medical progress. Any population projection that is based exclusively on past trends of demographic rates is bound to miss possible future dicontinuities and surprises. If they can be anticipated at all, it can only be done by considering demographic trends in a broader socioeconomic, cultural, and biological context. Here, the three components of population change--fertility, morality, and migration--are addressed. Introductory chapters describe past trends and assumptions for projections currently made in Europe and North America. Also included are discussions and analyses of some possible demographic discontinuities, together with a description of how assumptions on the three components are merged for population projections on national and international levels. This includes a synthesis where alternative views are translated numerically into ten alternative demographic scenarios for East Europe, West Europe, and North America through the year 2050.