In this essay, I provide an extensive review of the theoretical and empirical contributions pertaining to human capital. The first part follows the development of the theory with special emphasis, naturally, on Becker's path-breaking work (JPE '62 and Woytinski Lecture) and also on Ben-Porath's (JPE '67) paper. We then review the work of Mincer (JPE '58 and '62, NBER '74) who, more than anybody else, contributed to the empirical implementation of the theoretical concepts. The empirical section surveys the papers which have made use of direct and indirect measures of human capital. In the latter case, where human capital is measured by the number of years on the labor market and the number of years with the current employer (representing firm-specific capital), we focus our attention on a series of three papers which have all tried to use panel data to deal with the question of individual and job-match heterogeneity, i.e. Abraham and Farber (AER '87), Altonji and Shakotko (ReStud '87), and Topel (JPE '91). In the section on the explicit measures of human capital, we survey the burgeoning literature on the impact of various measures of skill acquisition on the wage profile. Finally, we conclude on some open questions like industry-specificity of human capital vs. firm-specificity.