The ability to project population trends is of vital importance for anyone involved in planning -- in the public as well as the private sector. This book provides the tools for making such projections and discusses four principal approaches: mathematical extrapolation, comparative methods, cohort survival and migration models. Primarily written for courses in planning, this book is also useful for anyone having to make decisions affected by population trends, whether they involve planning for future growth or alerting local decisionmakers to external uncertainties that could have a serious impact on the future of the community.