This book is written for young students in high schools and normal schools. No knowledge can be of more use to a young person than a knowledge of himself, no study can be more valuable to him than a study of himself. A study of the laws of human behavior, -that is the purpose of this book. What is human nature like? Why do we act as we do? How can we make ourselves different? How can we make others different? How can we make ourselves more efficient? How can we make our lives more worth while? This book is a manual intended to help young people to obtain such knowledge of human nature as will enable them to answer these questions.