Jorgenson’s 1963 paper, “Capital Theory and Investment Behavior,” introduced all the important features of the cost of capital employed in the subsequent literature. His principal innovations were the derivation of investment demand from a model of capital as a factor of production, the incorporation of the tax treatment of income from capital into the price of capital input, and econometric modeling of gestation lags in the investment process. In 1971 Jorgenson surveyed empirical research on investment in the Journal of Economic Literature. In the same year he was awarded the John Bates Clark Medal of the American Economic Association for his research on investment behavior. In 2011 Jorgenson’s paper was chosen as one of the Top 20 papers published in the first 100 years of the American Economic Review.