This completely restructured, updated third edition of the volume first published in 1992 provides a general overview of the econometrics of panel data, both from a theoretical and from an applied viewpoint. Since the pioneering papers by Kuh (1959), Mundlak (1961), Hoch (1962), and Balestra and Nerlove (1966), the pooling of cross section and time series data has become an increasingly popular way of quantifying economic relationships. Each series provides information lacking in the other, so a combination of both leads to more accurate and reliable results than would be achievable by one type of series alone. Much work has been done over the last four decades: investigation of the properties of the applied estimators and test statistics, analysis of dynamic models, the effects of eventual measurement errors, etc. These are just some of the problems addressed by this work. In addition, some specific difficulties associated with the use of panel data are also explored, such as attrition, heterogeneity, selectivity bias, pseudo-panels etc. Recently, much work has been done about unit roots and co integration using panel data. Some other fields have also experienced a strong development such as the econometrics of policy evaluation and the analysis of qualitative and truncated dependent variable models, among others, which all are also discussed. The third, enhanced edition provides a complete and up to date presentation of these theoretical developments as well as surveys about how these econometric tools are used to study firms and household s behaviors and/or more macroeconomic phenomena such as economic growth. It contains sixteen entirely new chapters while the others have been largely revised to account for recent developments in the field. Part I is concerned with the fundamentals of panel data econometrics, both linear and non linear; Part II deals with more advanced topics such as dynamic models, simultaneity and measurement errors, unit roots and co integration, incomplete panels and selectivity, duration and count models, etc. This volume also provides insights into the use of panel data in empirical studies. Part III deals with surveys in several major fields of applied economics, such as investment demand, foreign direct investment and international trade, production efficiency, labour supply, transitions on the labour market, etc. Six new chapters about R&D and innovation, wages, health economics, policy evaluation, growth empirics and the impact of monetary policy have been included.