The origin of this volume and the symposium proceedings it records can be traced to the deliberations of the National Academy of Sciences' Animal Orientation and Tracking Committee of the 1969 Space Biology Summer Study at Santa Cruz, California, whose members pointed to the potential role of satellites and recent bioengineering developments as a means of gaining information about the many questions of animal travel, particularly the mechanisms involved in long-distance navigational ability. Coming several years since its predecessor conferences, at a time of a new popularization of ecology and a growing availability of advanced technology, the Wallops Station symposium reflected its temporal and geographic setting. The papers and discussions of this volume contrast the classical approaches to phenomena of ancient interest, the beginnings made in applying satellite technology, and the conceptual and methodological advances in experimental biology which have taken place in the past few years. The range of species, sensory modalities, and methodologies provide the reader with a substantial sample of the developments in this field and with the basis for predicting, to some degree, its future course. Already apparent is the combining of field observations made under highly variable natural conditions with analytic, manipulative laboratory methods. A greater precision in the experimental questions now being posed is making their solution increasingly susceptible to neurophysiological and behavioral techniques for isolating the variables, both internal and environmental, which control this class of behavior. Whether the mechanisms of orientation and navigation will yield to the current array of approaches addressed to specific questions or must await a more general understanding of brain function, there is little doubt that this symposium will have had a significant effect on the research to be reported whenever the participants in this field again assemble to assess their progress. Richard E. Belleville Bioscience Programs