From The New England Journal of Medicine Cardiovascular disease is still the chief cause of death in our society. It is therefore not surprising that the field of cardiovascular science continues to expand rapidly, particularly at the cellular and subcellular levels. This expansion can cause difficulties for clinicians and medical students. Yet an understanding of the "new" physiology is essential for the proper use of new forms of medical technology and pharmacologic agents. It is in this context that Lionel Opie's opus expertly integrates cellular and subcellular elements of cardiovascular physiology in an analysis of physiologic responses. The book starts with an overview of the cardiovascular system, including descriptions of electrophysiologic principles, excitation-contraction coupling, and mechanisms of receptor and signal transduction. The discussion of these mechanisms then leads to a review of cardiac function and finally, to an integrative analysis of the circulation and pathologic conditions that affect it. A particularly strong feature of this book is that the discussion always goes back to cellular and subcellular mechanisms, maintaining the connection between cellular physiology and overall integrative physiology. An omission from this otherwise comprehensive book is a discussion of molecular mechanisms. There is nothing on transcriptional and translational regulation of enzyme systems and receptors, nor is there much information about new experimental mod