Investing in people : the economics of population quality / Theodore W. Schultz. Population quality. Schultz, Theodore W. (Theodore William), 1902-1998. Human capital. Education. HD4904.7 .S37 306.3 19 SCH Includes index. Bibliography: p. 149-166. Berkeley, Calif. : University of California Press, c1981. c1981. 1981 Text xii, 173 p. ; eng The Royer lectures ; 1980