The purpose of this paper is to examine four fundamental characteristics of the community psychologist's role. Understanding the nature of these characteristics is important to the development of community psychology. They are marginality, complexity, informality, and evolvement. Marginality is a consequence of the separateness of the change agent from the host system. This separateness promotes access and mobility, which facilitates the process of change. Complexity is inherent in encountering problems, learning requisite skills, and making ideological and ethical judgements. Informality is a characteristic necessitated by limited knowledge and the threatening effects of introducing change. Evolvement describes the constant emergence of community psychology, its progression from the crude to the sophisticated, and the importance of its historical roots to its future. Implications of these characteristics for the training of community psychologists are also discussed.