Iv Preface The highly developed form of the problems and exercises has also the effect of making the book elastic. By omitting a number of them, or by assigning some of the problems to individuals for report to the class, the whole subject can be covered in half a year. If all parts are carefully studied, the book provides material for a well-rounded course of a year. The original draft of this book was to a large extent the work of the junior author, whose lamented death occurred before the book had received its final revision. Mr. Cushing was responsible for the general plan of the book, and for its development along the lines of the four great economic fields. To him also is due the pedagogical method illustrated in the text and problems, and especially in the problem chapters at the ends of the four sections. It should be added, however, that since Mr. Cushing’s death the book has been com- pletely rewritten to bring it up to date. The. death of Mr. Cushing makes it impossible to acknowledge all the various sources from which help was received. Therefore, rather than acknowledge the kindness of some and omit others, it has seemed wise merely to express deep appreciation for the services of all who have had a part in the book, and to omit personal acknowl- edgments. The work of Miss Lenox E. Chase of the Mount Vernon High School of Commerce, however, must be mentioned, for Miss Chase has had an important share in the preparation of the exercises and tables. As a student of Mr. Cushing’s she knew and practiced his methods, and her assistance has been most valuable throughout. Acknowledgment is also due to the United States Department of Agriculture for most of the maps of crops and animals, which form an important feature of the book. The Department is doing a truly remarkable work in collecting, mapping, and disseminating statistics on a great variety of agricultural subjects.