This book presents a historical panorama of the evolution of demographic thought from its eighteenth-century origins up to the present day, and uses it to demonstrate how the multilevel approach can resolve some of the contradictions that have become apparent and achieve a synthesis of the different approaches employed. Part one guides the reader from period analysis to multilevel analysis, examining longitudinal and event history analysis on the way. Part two is a detailed account of multilevel analysis, its methods, and the relevant mathematical models notably as regards the type of variables being used. Numerous examples, examined across successive sections, make the book clear and easy to follow. The theoretical and epistemological treatment of these problems, during which the foundations of sociology and demography are revisited, and the logical development that leads to the most recent approaches, are handled sufficiently rigorously to satisfy social science specialists while remaining accessible for readers new to the field. The whole adds up to a comprehensive account of progress in sociological and demographic savoir-faire, as well as being both a textbook and an assessment of the multilevel analysis that tackles one of the major problems of empirical sociology: that of integrating analysis at the individual and group levels.