H.C. Engelbrecht (1895–1939) received his PhD at Columbia University, with a dissertation on Johann Gottlieb Fichte. While teaching at the University of Chicago, he wrote the bestseller Merchants of Death (1934) with F.C. Hanighen.
Ludwig von Mises: "Interest is the difference in the valuation of present goods and future goods; it is the discount in the valuation of future goods as against that of present goods." - Planning for Freedom