Although the importance of calcium (Ca²⁺) in the maintenance of cardiac contractility was recognized as early as 1880, the critical role of the ion in the contractile process in skeletal, cardiac, and smooth muscle has only been established within the last three decades. As the complexity of the pharmacological actions of the Ca²⁺ channel inhibitors grows, there is a continued need to further clarify the inhibitors, both chemically and functionally. This volume provides an update of the field based on the work presented at the 5th International Symposium on Calcium Antagonists: Pharmacology and Clinical Research. It reviews the current state of the growing area of molecular biology of Ca²⁺ channels. In the cardiovascular area, in addition to the well-established clinical uses of Ca²⁺ channel inhibitors, exciting new work pointing to an application in atherosclerosis is described. The book also includes important uses of Ca²⁺ antagonists in novel areas of interest such as the gastrointestinal tract, renal protection and multi-drug resistance.