An outstanding characteristic of the nervous system is that neurons make selective functional contacts. Each neuron behaves as if it recog- nizes the neurons with which it associates and rejects associations with others. The specific interneuronal relationships that result define the innate neuronal circuits that determine the functioning of this system. The purpose of this volume is to present some approaches to the problem of neuronal recognition. The volume has been somewhat arbitrarily divided into three sections. In the first section, the overrid- ing theme is the degree of specificity...