Psychedelic Horizons (Societas)
"An outstanding study of the human mind and what may actually be  beneficially derived from the use of psychedelic experiences." --Midwest review of books"Psychedelic Horizons is a good introductory overview of some  important topics in transpersonal psychology." --L.M. Leitner, PsycCritriques (APA Review of Books)"Roberts's ideas are described in a refreshing and  personal way.  A fascinating examination of the possibilities for the human mind." --High Times