This essay has, since it was first published in 1956, been regarded as a classic statement on sociological method. Here it is combined with two other of the author's essays. His study represents a departure from traditional sociological and philosophical theories of knowledge. It explores how people orient themselves in their world, by means of ideals, fantasy beliefs, wishful thinking, fact-related knowledge or feeling impulses, such as hope and fear. The author argues that the structure of knowledge in any particular field and the social level of danger or fear in that field or in society at large are interdependent. If one of them changes in a particular direction, the other, sooner or later, is likely to change in a corresponding direction. The concepts "involvement" and "detachment" are indicators of these directions. In highly developed societies knowledge is split. It has reached a relatively high level of detachment in the field of non-human nature while knowledge of human societies and of human beings generally represents a high level of involvement. The human picture with which the author works is no longer the derivative of an isolated individual. Hence a host of traditional concepts connected with this idea such as transcendentalism and positivism lose their function and meaning. Like magic-mythical concepts of nature, ideological concepts of society become recognizable as forms of knowledge which are more involved than detached. The empirical evidence shows a long-term process of change from dominant involvement to dominant detachment in people's knowledge and experience of non-human nature which is not matched by a corresponding directional change in the standard knowledge of human societies and their individual members.