These two volumes bring together theoretical and empirical papers on the economics of training. The first volume comprises of papers that discuss the economic theory underlying firms' and individuals' decisions to provide or acquire training. In particular, they offer differing perspectives on human capital theory. This volume also includes papers examining the design of both experimental and nonexperimental strategies for estimating the effects of training. The second volume consists of studies that estimate the impact of both public and private provided training on earnings. Most of the volume is devoted to studies that illustrate nonexperimental evaluations of training. However, because experiments have become an important part of this literature, the volume includes papers that provide a detailed evaluation of one well-known social experiment, and that use experiments to evaluate the non-experimental evaluations of training.