This book is a compendium of the written contributions submitted by the invited speakers to the 40th Annual Meeting of the Society of General Physiologists, held in Woods Hole, Massachusetts, during September 4-7, 1986. Our goal was to bring together investigators who work in different systems and are interested in the regulation of intracellular calcium and the modulation of cellular events, especially at the plasma membrane, that are mediated by alterations in intracellular calcium and associated events.