This book does an excellent job of giving not just the basics of what we know about human hearts, but also of telling the reader why we know what we know. I'm more interested in crocodilian than mammalian hearts, and this book usually provides enough detail to know if the concept being described is about vertebrates, mammals, or just about humans.I think this book has a lot to offer for people with widely different levels of expertise; it starts from a pretty basic level (assuming you have a solid grasp of general physiology but no expertise) and integrates a lot of information from very different fields and approaches. So if you know one slice of cardiac physiology very well, this book should still be able to help you fit that knowledge into a broader context.