This one-volume encyclopedia examines key topics, major world players, and imminent problems pertaining to the world's ever-growing population. According to the United Nations, the population of our planet reached 7 billion people in 2011. What areas of the world have the most people? What measures, if any, are in place to control the population? Why is Europe's population shrinking, while the rest of the world is growing? This eye-opening encyclopedia answers questions like these by examining significant issues and topics relating to the population and exploring profiles of the most populated countries and cities of the world. More than 100 alphabetically arranged entries focus on such topics as census, demography, megacity, overpopulation, and urban sprawl. Author Fred M. Shelley, an accomplished academic in the field of environmental sustainability, reveals the steps taken by major cities such as Rio de Janeiro, Paris, Tokyo, Beijing, Mexico City, Seoul, Manila, and New Delhi in handling their population, and what is being done in China and other countries to prevent overcrowding. The text includes a discussion of how factors like migration patterns, war, and disease impact population change. This comprehensive encyclopedia also includes primary document excerpts from court cases, legislation, and political speeches relating to population issues.