The Squirrel Monkey is devoted to the common South American squirrel monkey, Saimiri sciureus. In light of the growing number of squirrel monkeys being established each year in many laboratories, there appeared the need to pool existing knowledge in concise form. The present volume, the first of its kind on any single primate, attempts to meet this need. The topics that have been selected cover thoroughly areas of research in which Saimiri has been utilized. This material ranges widely from taxonomy and behavioral studies through husbandry and clinical management of the species, to investigations in aerospace medicine and in a number of basic biological sciences. Since the problems encountered in the squirrel monkey, though sometimes taking a particular form, are not unique in principle, the authors have attempted to provide an appropriate phylogenetic context for their material. It is hoped as a result that this compendium may serve as a valuable source of information during various phases of work on other subjects of primatological and comparative biological investigation as well.