The volume contains an up-to-the-minute account of direct investigations into the role of calcium ions in cellular function. Information on the operation of calcium channels in the plasma membrane and the release of calcium from intracellular stores, especially by recently discovered inositol phosphates and the long investigated methyl xanthines are all dealt with at a level of the most modern methodology. The role of the ubiquituos Ca-Na exchanger, Ca-ATPase and calcium binding proteins are given detailed coverage with an account of chemical agents modifying these functions. Details of the interactions of Ca with known receptors such as calmodulin, troponin C, Ca sensitive ion channels and protein kinase C are all given expert treatment. This volume would not be complete without consideration of the chemistry of the Ca ion itself, ions which can substitute for Ca, in some instances producing toxic effects such as with lead, and the role of Ca in bone formation.