Educational leaders are seeing with increasing clearness the necessity of teaching students not only the subject-matter of study but also methods of study. The recognition of this condition is taking the form of the movement toward ''supervised study,'' which attempts to acquaint the student with principles of economy and directness in using his mind. It is generally agreed that there are certain ''tricks'' which make for mental efficiency, consisting of methods of apperceiving facts, methods of review, devices for arranging work. Some are the fruits of psychological experimentation; others are derived from experience. Many of them can be imparted by instruction, and it is for the purpose of systematizing these and making them available for students that this book is prepared.