This book is based on papers presented at a Symposium held in Seoul, Korea in 1992. The idea for the symposium developed naturally from work by the editors and their colleagues on the possible role of certain amino acids, like taurine, that are strongly concentrated by the cells of the heart, and the relationship between such acids and membrane ionic currents. The first obvious question was whether it is possible to identify the transport mechanisms involved for taurine and whether they are electrogenic. The second question is what function could be served by such processes: does taurine play an essential role in cardiac tissue and is this important in protecting the heart from disease? A number of the world’s leading cardiac electrophysiologists and taurine specialists attended the symposium to discuss these questions. The papers in this volume range all the way from fundamental research on ionic current mechanisms in the heart to the use of taurine in clinical practice.