In most jurisdictions of Western societies, sudden and unexpected deaths are mainly due to natural causes linked with heart diseases by an initiating factor triggering cardiac arrest. That prompted us to write this book, which presents the pathology of the heart and cardiovascular system with a forensic perspective. The aim is to provide a background of facts currently known or believed with a critical review to aid the reader in resolving cases for which he or she is responsible. In other words, we revisit pathologic findings versus etiopathogenetic hypotheses and theories and propose new ones substantiated by previously misinterpreted or ignored facts. In this book, detailed findings are presented along with overall interpretations to help the forensic pathologist in a court of law to act as interpreter of the sequence of events leading to death.