The author presents this book to the public with great enthusiasm: it contains so much unfamiliar content that one cannot easily accept its message; it has become too complex to quickly win the hearts of clinicians. It requires thorough study before it can achieve its goal: better diagnostics. This work attempts to apply the physically grounded knowledge of the present regarding electrophysiological processes to all areas of the ECG. We have advanced to an exact theory of all leads, particularly the precordial leads. There can be no more dispute regarding the question of partial derivation; the ECG has been largely made calculable, except for the unpredictable errors caused by the inhomogeneities of the thorax with its variable conductivities. Thus, this book contains original insights.