In this first decade of the 2000s an impressive increase of knowledge took place in the field of arrhythmogenic right ventricular cardiomyopathy, a disease that was discovered as a clinical entity only 30 years ago. A panel of international experts from both sides of the Ocean contributed to this issue of Cardiac Electrophysiology Clinics. Molecular genetic investigations established that this hereditable cardiac disorder is a cell junction disease, due to mutations of genes encoding desmosomal proteins in charge of the mechanical coupling. Transgenic mice have been generated to elucidate the pathogenetic mechanism of the cell injury, namely, genetically determined cell death followed by fibro-fatty replacement and ventricular electrical instability. New diagnostic criteria have been put forward, including quantitative parameters and T-wave inversion in right precordial leads, ventricular tachycardia of left bundle branch block morphology with superior axis, and daily frequency of more than 500 ventricular extra-systoles as major criteria. Identification of pathogenetic mutations is considered as an additional instrument of diagnosis. The employment of cardiac magnetic resonance imaging has become a widespread tool, for both morphofunctional analysis and tissue characterization. The implantable cardioverter defibrillator has been revealed to be an extraordinary lifesaving therapy, not only for secondary prevention after aborted cardiac arrest but also for primary prevention following syncopal episodes. Electroanatomic mapping may be considered an in vivo virtual histology, with low-voltage areas corresponding to fibro-fatty myocardial atrophy, and may be accomplished from either the endocardial or the epicardial side, as to be fundamental to guide catheter ablation. Cardiac arrest in this disease may be precipitated by effort. It has been proven that sudden death in athletes can be prevented mostly by recognition of cardiomyopathies, such as arrhythmogenic and hypertrophic, during preparticipation screening followed by disqualification from sports activity. By reading the title and the various articles in this issue, the reader will see that we intentionally introduced a new terminology, namely arrhythmogenic cardiomyopathy “tout court,” ruling out the label “right ventricular” to underlie the evolving concept of a genetically determined heart muscle disease extending across the entire heart. Even though we are excited about the terrific advances achieved, we have to admit that only symptomatic therapy is still available. Although the genetic causes of the disease are now well known, we do not understand yet how mutations of genes encoding desmosomal proteins are responsible for cell suicide/death. We need to know more about intracellular signaling linking intercalated disc to cell function and viability, and certainly the transgenic mouse models will help for mechanistic insights, with the hope that the discoveries will be translated soon to the clinical setting for a curative therapy. The Editors and their groups are supported by the Fondazione Cariparo, Padova and Rovigo; and by the Registry of Cardio-Cerebro-Vascular Pathology, Veneto Region, Venice, Italy. The research was carried out within a grant from the European Commission, Brussels, Belgium (QLG1-CT-2000-01091). They also acknowledge the Association for Research of Arrhythmic Cardiac Diseases (ARCA, via Gabelli, 61, 35121 Padua-Italy) and Chiara Carturan for the assistance in preparing this book.