This primer of inflammation biology introduces the cast of characters under consideration in subsequent contributions to this volume—a cast that has mushroomed in recent years. It describes the mechanisms of innate and acquired immunity, and the key players in the inflammatory response, explicating and disentangling the connections between them—the better to argue its case that the entire spectrum of inflammatory diseases represents host defenses gone awry. A number of cardiovascular conditions, some exotic, but many common, involve an important component of inflammation, representing host defense mechanisms that can cause disease. The recognition of the central role of inflammatory pathways in circulatory pathophysiology furnishes a new dimension to understanding even the most familiar and clinically compelling cardiovascular diseases, notably atherosclerosis and acute myocardial infarction, each of which is discussed in detail. In addition, these inflammatory aspects of cardiovascular diseases may provide, in some cases, new therapeutic opportunities to forestall the development or the consequences of various cardiovascular conditions. Seemingly far afield at the outset, contemporary inflammation biology has concrete clinical ramifications for the practitioner. Learning to redirect inappropriate inflammatory responses may help us to improve patient outcomes in years to come...