From the PREFACE. Within the last decade psychology has become, in a sense, the gauge of all the sciences and the most basal of them all. Psychology has taken the place long held in common by chemistry and physics, a change which was inevitable for the best of reasons - that by natural necessity the science of mind underlies our whole knowledge of matter. With all this significant and potent progress psychology unquestionably has neglected some of its inherent obligations to the twenty-five million American students (twenty-two million of whom are in school) who are expending precious time and energy and money in learning - some of them, to speak more accurately, in trying to learn. This vast multitude of our youths and maidens are making confident investment of their young years, the best they have or ever will have, in the wholly necessary means of future livelihood and anticipated happiness for themselves and their hoped-for families. Academic psychology with its highly productive resources gladly owns to these the obligation of giving all it can to make this learning-process easier, more pleasant, and in all ways more productive. The present handbook strives toward the attainment of this high utilitarian aim. For this not unworthy purpose it employs in part both the newer, important, concrete discoveries and wider points of view reached in the last few years of educational discussion, as well as the often more familiar pedagogic material derived in the slow ages of school-experience alone, now more and more discredited. Because of the complete mutual interaction and integration of "mind" and "body" in the individual, practically everything in this book applies in some degree or other, - and when properly adapted, as accurately, - to motor learning, to the growth of bodily skill in all its phases, as to that learning popularly called "mental." To learn is to become able, and ability is always both organic and psychical. The advice is written for the learner, but oftentimes the learner may best obtain it through the intelligent teacher - a responsible privilege some teachers ignore. Those students will heed it most who realize to the effective degree that the saving principles of economics should underlie every rational endeavor, allowing neither time nor energy nor other of the riches of our precious, passing youth to be wasted. The one aim of the book, then, is to be of some immediate, practical use to those, young or old, who, in our workaday world, are engaged, whether vocationally or otherwise, in intensive learning. In these days of highly organized play and recreation, often of an elaborate nature, it is worth noting that these principles and hints apply as well in this field as in that of education proper. Part of the first chapter has been published already, and under its present title, in "The Medical Record", New York, and is reproduced here through the kindness of the editor, Dr. Thomas Lathrop Stedman. Part of the substance of the other chapters appeared as a serial in "The Scientific American Supplement" in the spring of 1916. The author hereby expresses his cordial thanks to the scholars whose work and wisdom he has made use of, whether with or without explicit license....