The book provides a comprehensive overview of the principles, methods, and policy dimensions of population studies. The text is designed to lay a foundation for students, researchers, and practitioners in disciplines such as economics, statistics, sociology, geography, and public policy. Comprising twelve chapters, the book begins with the meaning, scope, and historical evolution of demography, and its relationship with allied disciplines. It then discusses classical and modern theories of population, including Malthusian, post-Malthusian, biological, sociological, and demographic transition theories. Subsequent chapters explore the major sources of demographic data, techniques of population projection, and the changing composition of populations with respect to age, sex, and socio-economic attributes. Special emphasis is placed on core demographic processes?nuptiality, fertility, mortality, morbidity, and health?supported with conceptual clarity, measurement techniques, and empirical illustrations. The book also addresses critical themes such as urbanization, migration, population-development linkages, and the interrelationship between population and environment. The final chapter provides a detailed account of population policies and family welfare programmes in India, highlighting their evolution, achievements, and ongoing challenges. Drawing upon both theoretical insights and empirical evidence by the experts in the three different best related fields, the book seeks to blend academic rigor with clarity of presentation. It aims to equip readers with the tools necessary to understand demographic dynamics and their implications for development planning and policy formulation. This text will be particularly useful for undergraduate and postgraduate students, competitive examination aspirants, and scholars working in the field of population studies.