There is increasing recognition of the biological importance of taurine. Disturbances in taurine metabolism are seen in dysfunctional states as diverse as epilepsy, cardiomyopathy, Friedreich's ataxia and congestive heart failure, which combined with the antiepileptic and cardiotonic actions of taurine underscore the emerging clinical importance of this fascinating substance. This is the third book to appear on taurine since 1976. The last book (Taurine and Neurological Disorders, Raven Press, 1978) emphasized the involvement of taurine in central nervous system phenomena. These actions are further explored in this volume. In addition, nutritional aspects of taurine, particularly as these relate to development, have been increasingly recognized to be important parts of the taurine story. The marked emphasis placed on nutrition by a number of contributors to this volume is recognition of the meteoritic growth of this area. Are the multitudinous actions of taurine differential expressions of a universal mechanism? There is surprising unity of opinion expressed by the scientists contributing to this volume, despite their differences in viewpoint and background, as the reader, tantalized we hope by this remark, will discover. This volume is the outcome of a Symposium, "Taurine: Questions and Answers" held at the Universidad Nacional Autdnoma de Mdxico in November, 1980. An unusual aspect of the meeting was the devotion of half the time to open, relatively unstructured, discussions of various problems in taurine research. Transcripts of these discussions are included in this volume, and the editors hope that workers both well aquainted and peripheral to the area will find them of value.