Present knowledge of the mechanisms underlying any single sensory modality is so massive as to discourage effort directed towards completeness. The idea underlying the structure of this volume on "Sensory transduction" was to select just a few topics of general interest, which are currently being investigated and for which a reasonably clear picture is now available. During the last five years there has been a revolution in the way sensory physi- ologists think about transduction, and a series of exciting advances have been made in understanding the basic processes of photo transduction,...