The family is a complex decision unit in which partners with potentially different objectives make consumption, work, and fertility decisions. Couples marry and divorce partly based on their ability to coordinate these activities, which in turn depends on how well they are matched. This book provides a comprehensive, modern, and self-contained account of the research in the growing area of family economics. The first half of the book develops several alternative models of family decision making. Particular attention is paid to the collective model and its testable implications. The second half discusses household formation and dissolution and who marries whom. Matching models with and without frictions are analyzed and the important role of within-family transfers is explained. The implications for marriage, divorce, and fertility are discussed. The book is intended for graduate students in economics and for researchers in other fields interested in the economic approach to the family. "This very fine book by three prominent economists - Browning at Oxford, Chiappori at Columbia, and Weiss at Tel Aviv - will provide an invaluable tool not only to population economists but also to labour economists (especially those with an interest in explaining the gender gap) and all economists with an interest in inequality and household consumption (which is to say, almost all economists)." Canadian Studies in Population This book provides a comprehensive, modern and self-contained account of the research in the growing area of family economics. Martin Browning is Professor of Economics at the University of Oxford and the Director for the Center for Applied Microeconometrics in Copenhagen. He is a fellow of the Econometric Society, the European Economic Association, and the British Academy. Professor Browning was awarded the John Rae Prize in 1996. Pierre-André Chiappori is E. Rowan and Barbara Steinschneider Professor of Economics at Columbia University. He is a fellow of the Econometric Society, the European Economic Association, and the Society of Labor Economists. Professor Chiappori was awarded the Grand Prix Zerilli Marimo de l'Académie des sciences morales et politiques in 2010. Yoram Weiss is Professor Emeritus at Tel Aviv University. He is a former president of the Society of Labor Economists (2008) and a winner of the Mincer Prize for lifetime contributions to the field of labor economics (2009). Professor Weiss was editor of the Journal of Labor Economics from 1993 to 2005.