In spite of old vintage and 200 years of clinical use, digitalis remains an interesting therapeutic agent, to clinicians as well as to the pharmacologist, the biochemist, and colleagues in other diciplines of theoretic medicine. When a drug, however, has so many attractive facets, it seems proper and aJvisable for the success of a scientific meeting to focus on a number of well-defined aspects. This symposium was devoted to pharmacokinetics, drug metabolism, analytic procedures, blood level determinations, and their interpretation both for therapeutic and toxic situations. Considerable progress has been made during the last years in this area of digitalis research. The time was suitable for a critical reappraisal of facts and theories and for future planning. Our main intention was to relate analytic data and biochemical findings to clinical problems and questions. Despite the undoubtedly basic character of clinical pharmacology, it is nevertheless an applied science which should help to develop the rational basis of therapeutics. We are particularly grateful to the active participants who bore the burden of preparing presentations and - even worse - manuscripts. At the same time we are well-aware that many other active research groups would have been able to contribute in this way, but our program was limited because of the short time available. Their knowledge is included in the discussion parts of the meeting, so we hope a well-balanced description of the present state of affairs emerged in this volume.