While theoretical and empirical research on the economics of human capital is still in its relative youth, a substantial body of work has already accumulated on the variables determining worker earnings and on the importance of schooling as one of those determinants. The present paper focusses attention on one such variable that has received almost no attention in the literature, namely, experience. The concept of experience is explored, its various forms examined, and then a number of operational measures of experience in models of individuals' earnings are applied. The primary objective is to learn more about the quantitative importance of experience as one (or more than one) determinant of earnings. Also investigated is the quantitative importance of schooling as a determinant of earnings. Regression estimates are sensitive to the specification and measurement of experience. A body of data is analyzed to assess both the quantitative importance of the various types of experience and the effect of their inclusion on the estimated co-efficient of schooling. This body of data is drawn from a national sample of 3000 male veterans aged 18-35, who were included in the 1964 Current Population Survey. Data for the 965 men for whom complete information was available on the variables of interest was used. (Author/JM)