The kindly reception accorded to the first edition of this book has confirmed the author in his conviction that such a book was needed, and has tempted him to bestow additional labor upon it. The chief changes consist in the addition of two new chapters, "Active Imagination," and "How to Develop Interest in a Subject"; the division into two parts of the unwieldy chapter on memory; the addition of readings and exercises at the end of each chapter; the preparation of an analytical table of contents; the correction of the bibliography to date; the addition of an index; and some recasting of phraseology in the interest of clearness and emphasis.

The author gratefully acknowledges the constructive suggestions of reviewers and others who have used the book, and hopes that he has profited by them in this revision.

H.D.K.

April 1, 1921.