People=s faith determines both their personal understanding of the world and of themselves, as well as their place in society. In addition to traditional religions and individual spirituality, non-religious ideological belief structures and also liberal worldviews exist. Faith & understood as an elementary imaginative, affective and cognitive mixed function of the human psyche & therefore deserves greater attention in everyday psychiatric and psychotherapeutic practice. This volume discusses spirituality and the diversity of religious belief in today=s world both from the therapeutic point of view and in relation to its development in the history of humanity. It emphasizes the basic hypothesis that there is a ?reciprocal entanglement= of the poles of faith and knowledge relative to mental health and illness. In his plea for a tolerance of ambiguity in dealing with patients= religious worlds, the author reflects on cultural studies, medical and psychotherapeutic sources, and, last but not least, Karl Jaspers=s positions and analyses.