The last several decades have each been broadly characterized by one or two central economic questions. In the 1920's the central problem was international capital transfers, or reparations and war debts; in the 1930's, the international spread of unemployment and destabilizing speculation; in the late 1940's, after the war, reconstruction; in the 1950's, defense economics and growth.
Not only can we identify them; it is on the whole fair to say that the central problems of the 1920's, 1930's, and 1940's have been solved. International capital transfer is accomplished by preventing war debts from accumulating, paying limited reparations in kind, and furnishing the capital needed for reconstruction, and in part for economic growth, as grants or on liberal loan terms.