Discerning readers will not fail to notice the pioneer quality of Mr Morgan's essay. They will also observe that its novelty lies not so much in its matter as in its theme. It is not that the matter is in any way hackneyed or stale. There are many things in the book which at least one reader found wholly new, and which other and more expert readers may find at least interesting. Yet the principal characteristic of the book is not the information which it contains, but the purposes for which the information is employed. Mr Morgan has set out to do what in the writing of modern economic history has so seldom been done. His study is both historical and theoretical, and though many students before him tried to marry economic history to economic theory, few of them ever achieved the union on Mr Morgan's terms.

Economic studies combining theory with history fall, as a rule, into two interrelated groups. They are conceived either as exercises in “applied economics” in which a few historical facts are used to illustrate the few economic theories which are capable of being illustrated; or else as “historical revisions” in which certain well-known episodes of economic history are re-told in terms of modern theory. Examples of the former will be found embedded in most of the better known economic treatises from Adam Smith to Marshall and Keynes. Examples of the latter have been lately produced by economists and historians alike: vide Bresciani-Turoni's book on the German inflation, Rostow's articles on the Great Depression, or Fisher's article on the commercial policy of the Tudors.

Mr Morgan attempts none of these things. While his debt to modern economic theory and more especially to Keynes will be obvious to all (and economic theories are an avowed part of his subject) he treats the theories themselves as historical facts and subjects them to historical analysis. At the same time the book is no mere “history of economic doctrine”. It pays an equal if not a greater attention to the banking policies, the monetary changes and the movements of prices, which sometimes influenced theoretical discussion and were often themselves affected by contemporary doctrines. The two topics are run on concurrent lines, which often intersect, but are never merged or confused.