As one who has gone down the wayward path from "pure" organic chemistry to biochemistry to pharmacology, I was not quite prepared to go all the way - into the field of discriminable stimuli. The organizer of the symposium on discriminable stimuli induced by drugs, Dr. Harbans Lal, did seduce me into attending. Having lost my behavioral virginity, I now stare with open eyes at the field. One item in particular at this meeting exemplifies to me the power of such techniques. Dr. Albert Weissman mentioned the problem he tackled with getting rats to discriminate between saline and dilute solutions of aspirin. Under ordinary circumstances, the animals could not perform this task. However, if the animals were sensitized by injection of prostaglan din into their foot pads, then they were capable of discriminating even very dilute solutions of aspirin. In a sense, Al had created a model of the human arthritic who can jolly well tell if you have given him an aspirin or a salt tablet. The reader of this volume will find it a good introduction to the utilization of discriminable stimuli induced by drugs. After a preface by the organizer, two experts discuss basic principles in separate chapters. One of these chapters places emphasis on the drugs; the other places emphasis on the induced cues and states.