The general topic of this volume is education on its intellectual side. One main idea runs through the various chapters, and it is illustrated in them from many points of view. It can be stated briefly thus: the students are alive, and the purpose of education is to stimulate and guide their self-development. It follows as a corollary from this premise, that the teachers also should be alive with living thoughts. The whole book is a protest against dead knowledge, that is to say, inert ideas. - Preface.