This conjunction of physical medicines—the psychedelics—with the ancient spiritual dynamics of healing reflects neurological concordances, an integration of psychophysiological and psychocultural dynamics. This is reflected in a fundamental adaptation found in all human societies in the form of shamanistic healing practices (Winkelman 1990, 1992, 2000). The particular emphasis upon psychedelics as a means of achieving this adaptation reflects the needs for cultures to reorient their psychocultural dynamics to the changes that have occurred in social and cosmological relations, producing new patterns of integration. This suggests that the use of psychedelics will continue in the rapidly changing world and requires that societies take informed approaches to their managed use. Our contributors take great strides in illustrating the scientific bases for the application of these psychedelic medicines to address crucial health problems, including some of the most vexing problems of our times, those associated with addictions.