Very fundamental changes in the nature of the world economy, principally World War I, war financing, the sensational inflation of the currencies of the combatants, and the remarkable developments in new scientific, industrial and agricultural methods had occurred; all requiring integration into a new theory. Fisher called interest "an index of a community's preference for a dollar of present [income] over a dollar of future income." He labeled his theory of interest the "impatience and opportunity" theory. Interest rates, Fisher postulated, result from the interaction of two forces: the "time preference" people have for capital now, and the investment opportunity principle (that income invested now will yield greater income in the future).

    In this new translation of two other seminal works by Mauriac, the 1930 novel What Was Lost and its theoretical basis, the 1929 essay God and Mammon, Raymond N. MacKenzie re-introduces Mauriac to the English speaking world. Featuring a scholarly introduction by MacKenzie that provides background on Mauriac's religious and artistic struggles, this new edition will delight scholars of Mauriac as well as contemporary readers previously unfamiliar with his work.