Authors, no doubt, are always gratified when their works find favorable acceptance. The writer of this text has been doubly gratified, however, at the cordial reception and widespread use accorded to the present volume. This feeling does not arise from any narrow personal pride or selfish interest, but rather from the fact that the warm approval of the educational public has proved an important point; namely, that the fundamental truths of psychology, when put simply and concretely, can be made of interest and value to students of all ages from high school juniors up, and to the general public as well. More encouraging still, it has been demonstrated that the teachings of psychology can become immediately helpful, not only in study or teaching, but also in business or profession, in the control and guidance of the personal life, and in the problems met in the routine of the day's work or its play. George Herbert Betts (1868-1934) was an American psychologist and educator, recognized for his contributions to educational psychology and the study of intelligence and learning. As a professor and writer, Betts played a pivotal role in shaping educational practices and theories.