This volume is an outgrowth of a dynamic interdisciplinary meeting sponsored by the National Institute of Mental Health (U.S.A.). Forty-six leading psychiatrists, pharmacologists, psychologists, biochemists and neurophysiologists have contributed papers and participated in vital, informative discussions on the nature, effects, and proposed mechanisms of action of the rapidly expanding group of mind-distorting compounds. The book is unusual in that the research presented deals with all levels of current interest: from the electro-physiological effects on single nerve cells to effects on the biochemical and metabolic levels; from structure-activity relationships to subtle clinical personality disorders.