Lack of space makes it impossible to mention by name the many sources to which the writer is indebted. Special acknowledgment, however, is gratefully made to C. H. Hull, of Cornell University; to E. W. Kemmerer, now of the Philippine Treasury Department, and to U. G. Weatherly, of Indiana University, who have read large portions of the manuscript, and have made many valuable suggestions; to W. M. Daniels, of Princeton University, who has read every page of the copy, and to whom are due the greatest obligations for his numerous and able criticisms both of the argument and of the expression; to R. C. Brooks, now of Swarthmore College, for a number of the questions in the appended list, and for helpful comments given while the course was developing; and to R. F. Hoxie and to A. C. Muhse, whose thoughtful reading of the proof has eliminated many errors. For the defects remaining, not these friendly critics, but the author alone, should be held accountable. No book on economics can to-day satisfy everybody--"Or even anybody," adds a friend. But with this book may go the hope that what has been written with love of truth and of democracy may serve, in its small way, both to further sound economic reasoning and to extend among American citizens a better understanding of the economic problems set for this generation to solve. FRANK A. FETTER. Ithaca, N. Y., August, 1904. THE PRINCIPLES OF ECONOMICS PART I DIVISION A--WANTS AND PRESENT GOODS CHAPTER I THE NATURE AND PURPOSE OF POLITICAL ECONOMY § I. NAME AND DEFINITION [Sidenote: Verbal definition of economics] 1. _Economics, or political economy, may be defined, briefly, as the study of men earning a living; or, more fully, as the study of the material world and of the activities and mutual relations of men, so far as all these are the objective conditions to gratifying desires._ To define, means to mark off the limits of a subject, to tell what questions are or are not included within it. The ideas of most persons on this subject are vague, yet it would be very desirable if the student could approach this study with an exact understanding of the nature of the questions with which it deals. Until a subject has been studied, however, a definition in mere words cannot greatly aid in marking it off clearly in our thought. The essential thing for the student is to see clearly the central purpose of the study, not to decide at once all of the puzzling cases. [Sidenote: Natural sciences deal with material things]