Those who have contributed to this volume represent a wide spectrum of Humanist opinion in the world today. They are primarily philosophers, psychologists, social scientists, ethical and religious leaders. Among the themes they discuss are historic roots of Humanism, the general problem of definition, the relationship of Humanism to ethics and morality, Humanism and religion, Humanism and atheism and Humanism on the world scene.Most of the varieties of Humanism are represented, including naturalistic Humanism, liberal Humanism, atheistic Humanism, humanistic psychology, behaviourism, Marxism, and Zen. If there is a common thread running throughout this volume, it is the conviction that Humanism is committed to the method of reason as the chief means of solving problems and the belief that mankind can survive and humans can enjoy a significant life. This conviction and this belief, however, can be realised only if men continue to have confidence in their own natural powers and abilities and the courage to use them.