Students who may take up this book for serious study will get the greatest good from it by following prices of agricultural products from day to day and month to month, and noting when the relationship is normal and when abnormal. In this way they will acquire habits of intelligent observation of price trends that should prove of very great value to them when they get into business for themselves. If this book is used as a college text, it is hoped that it will be by classes which are especially concerned in applying statistical laws to agricultural prices. Such classes should have free access to calculating machines, multiplying tables, etc., and should make a serious effort to work out various ratios and also to work out supply and demand laws for various farm products by means of correlation coefficients, lines of regression, etc. The tables given in the appendix should be of some value as a source of raw material. For further material, it is suggested that the Year Books of the United States Department of Agriculture, the Monthly Crop Reporters of the Bureau of Crop Estimates, and the Reports of the Chicago Board of Trade be consulted. A good book on correlation coefficients, etc., is Yule’s Theory of Statistics. The teacher of the suggested class in agricultural price statistics should simplify the mathematics to mere method, not concerning himself or his pupils with the theory back of it all. Wherever possible, the teacher should study very carefully the January and April, 1919, volumes of The Review of Economic Statistics, published by the Harvard University Press. The methods as exemplified in these volumes can very profitably be applied to the field of agricultural prices. Acknowledgement is made to Professors J. M. Evvard and E. G. Nourse, of the Iowa State College, and to Professor F. A. Pearson, of the University of Illinois, for criticisms and helpful suggestions. HENRY A. WALLACE. [Illustration] TABLE OF CONTENTS