The volumes on "psychotropic substances" in the Handbook of Experimental Phar- macology series clearly show that the classical concept of this discipline has become too narrow in recent years. For instance, what substances are psychotropic is determined not by the criteria of the animal trial, i.e. by experimental pharmacology, but by their action on the psy- che, which in the final analysis is only accessible to us in man. Psychotropic substances force experimental pharmacology (and thus also this Handbook) outside its tradition- allimits, which have essentially depended on animal studies....