The electric field of the heart was described diagrammatically for the first time by A. Waller in 1888. However, it was not until a little more than ten years ago that with the development of micro­ electronic techniques, it became accessible to biophysical modeling, to exact physiological measurements, and to application in advanced clinical diagnosis. These possibilities opened the way to the treatment of questions which are called the direct and the inverse solution of the cardioelectric problem. Several groups of investigators are now working to achieve a complete biophysical and physiological description of the generation of the cardiac electric field. This work could well form the basis for a new method of diagnostic measurements, with applications even in clinical cardiology, delivering important information by a non­ invasive investigation of the patient. Several conferences have stimulated international exchange of the results of research on the cardiac electric field. Among others, the satellite symposium of the XXV International Congress of Physio­ logical Sciences on the electric field of the heart, in Brussels, August 2-3, 1971, and the Conference on Measuring and Modeling of the cardiac electric field, in Smolenice near Bratislava, June 14- 17, 1976, may be considered predecessors of the Dresden symposium the proceedings of which are presented in this volume.