Pancreatic a-cell biophysics has undergone a veritable information explosion in the past two years. Single channel and macroscopic currents have become easily accessible following the introduction of the patch clamp technique. In addition to this new approach, further development of techniques for optical measurements, ion-sensitive microelectrodes, permeabilized cells and mathematical modelling have recently added to the now classical techniques of membrane potential recording and tracer flux measurement. The International Workshop on Biophysics of the Pancreatic a-Cell held in Alicante (Spain) on Sep­ tember 30 - October 1, 1985, has now given us the opportunity to share experiences with these new techniques applied to the a-cell. Further­ more this was the first occasion for most of the groups doing patch­ clamp studies of the a-cell to decide on appropriate nomenclature and to debate the different characteristics of the a-cell ionic channels. To make this information available to the larger scientific community a record of the meeting has been assembled in this book. It is a collection of research papers by leading scientists at the meet­ ing working on biophysical, biochemical and physiological aspects. of secretion. We grouped their contributions in seven sections, includ­ ing new experimental approaches, K-channels, Ca-channels, role of ionic channels, intracellular ionized calcium, neural regulation and mechanisms of insulin release. Each section gives an account of the state of the problem at the time of the meeting, and the subjects are analyzed from the different perspectives of the various contributors.