The present book is a collection of panel data papers, both theoretical and applied. Theoretical topics include methodology papers on panel data probit models, treatment models, error component models with an ARMA process on the time specific effects, asymptotic tests for poolability and their bootstrapped versions, confidence intervals for a doubly heteroskedastic stochastic production frontiers, estimation of semiparametric dynamic panel data models and  review of survey attrition and nonresponse in the European Community Household Panel. Applications include the impact of  uncertainty on UK investment, a Tobin-q investment model using US firm data, technical change in the Japanese chemical industry, cost efficiency of Spanish banks, the problem of immigrant integration in Canada, an analysis of the dynamics of individual health in the UK, the relationship between inflation and growth among OECD and APEC countries, modeling corner solutions in the industrial energy demand in the pulp and paper sector in France, technical efficiency of cereal farms in England, employment-supported training in Canada, earnings trends across skill groups and industries in West Germany, employment effects of education for disabled workers in Norway, a three-way gravity model with bilateral interaction effects for APEC countries and a panel cointegration approach to the Feldstein-Horioka investment-saving puzzle.