"The Theory of Prosperity" may be regarded as a fusion of the economic philosophy which the author summarized in his "Dynamic Economics" with the results of the studies in social psychology presented in "The Theory of Social Forces" and "The Development of English Thought". But such a characterization is only partly true. Professor Patten has a well-earned reputation for originality, which his latest work will not diminish. In -act, there is an element of unexpectedness in Professor Patten's developments of his own theories which adds to the interest of any new work coming from his hand. The two general divisions of the book treat of "Income as Determined by Existing Conditions," and "Income as Determined by Heredity." "Economic forces rise out of existing conditions and exert an influence on the present race of men. Past environments influence through heredity, morals and traditions." It is the first of these two general divisions which is of greater interest to the economist. Professor Patten believes that the traditional classification of income as wages, rent, and profits has outlived its usefulness, since the recipients of these three forms of income no longer constitute distinct social classes. "These shares, instead of being distinct funds, are the bases of three viewpoints from which income may be regarded."