The main aim of this monograph is to provide an overview of calcium regulation in cardiac muscle cells, particularly with respect to excitation-contraction coupling and the control of cardiac contractile force. It is my hope that this book will be useful to students of the cardiovascular system and muscle at all different levels and in different disciplines (such as physiology, biochemistry, pharmacology and pathophysiology). I also hope that it will find use for those studying developmental, comparative and disease processes as well as more integrative phenomenon. I kept several goals in mind in writing this monograph. First, it should be easily readable. Second, I chose to include numerous illustrations and tables to help integrate results from numerous investigators in practical formats and also present key figures from important papers. Thus, this monograph may serve as a resource of information for people working in the areas described herein. Third, the presentation is a very personal one, and I have necessarily drawn extensively on my personal experience in this field over the past 15 years. This, I think, helps maintain a certain continuity of thought from chapter to chapter. Fourth, I have made serious attempts to make each chapter "up to date", despite the breadth of topics covered. I have also tried to be equitable in choosing references while not intending to be comprehensive or exhaustive. Neither of these aims can be perfectly matched, and I apologize to the many investigators whose papers I have not cited, but should have.