Since its publication in 1978, PRB's Population Handbook has appeared in eight languages and has been circulated around the world. It has been used by thousands of teachers and students in fields such as sociology, geography, and urban studies. Journalists refer to the handbook as an authoritative guide in preparing population-related stories, while policymakers and planners have found it to be a ready reference to the rates, ratios, and concepts of demography. Understanding the broad implications of population change is important to those who make decisions and inform others about demographic change around the world.