"The aim of this book is to make the study of teaching scientific and practical--scientific in the sense of dealing with verifiable facts rather than attractive opinions, practical in the sense of giving knowledge and power that will make a difference in the actual work of teaching. It follows the example of teaching upon the laws of psychology; it makes use of modern scientific psychology; it seeks to make use also of direct studies of teaching itself which have been made by qualified experts; it is arranged as a manual to guide the student in applying principles himself rather than as a series of discussions to be thought out or, more often, to be simply absorbed."--Preface.