The Nature of Capital and Income 2 is of that class of books that have kept the guild of theoretical economists content to do nothing toward “the increase and diffusion of knowledge” during the past quarter of a century. Of this class Mr. Fisher’s work is of the best-thoughtful, painstaking, sagacious, exhaustive, lucid, and tenaciously logical. What it lacks is the breath of life; and this lack it shares with the many theoretical productions of the Austrian diversion as well as of the economists of more strictly classical antecedents. Not that Mr. Fisher’s work falls short of its promise, and assuredly it does not fall short of the mark set by those many able men who have preceded him in this field. No reader of Mr. Fisher can justly feel disappointed in his performance of the difficult task which he sets himself. The work performs what it promises and does it in compliance with all the rules of the craft. But it does not set out substantially to extend the theory or to contribute to the sum of knowledge, either by bringing hitherto re-fractory phenomena into the organised structure of the science, or by affording farther or more comprehensive insight into the already familiar processes of modern economic life. Consistently with its aim, it is a work of taxonomy, of definition and classification; and it is carried 149through wholly within the limits imposed by this its taxonomic aim. There are many shrewd observations on the phenomena of current business, and much evidence of an extensive and intimate acquaintance with such facts of modern culture as are still awaiting scientific treatment at the hands of the economists (e.g., in chapters v and vi, “Capital Accounts” and “Capital Summation,” as also in chapters viii, ix, xiii, xiv, “Income Accounts,” “Income Summation,” “Value of Capital,” “Earnings and Income,” “The Risk Element”). But the facts of observation so drawn into the discussion are chiefly drawn in to illustrate or fortify an argument, somewhat polemical, not as material calling for theoretical explanation. As affects the development of the theory, these observations and this information run along on the side and are not allowed to disturb the argument in its secure march toward its taxonomic goal.