More people die of heart disease than any other disease in the world and when any form of heart disease progresses, it can result in the development of heart failure. Heart failure affects millions and can affect anyone at any time, a child recovering from a viral infection, a woman who has just given birth or a cancer patient receiving chemotherapy. Yet new technology to treat heart failure is fundamentally changing just what it means to be human. Mechanical pumps can be surgically sewn into patients’ hearts and when patients with these pumps get really sick, sometimes they don’t need a doctor or a surgeon—they need a mechanic. In State of the Heart, the journey to rid the world of heart disease is shown to be reflective of the journey of medical science at large. We are learning not only that women have as much heart disease as men, but that the type of heart disease women experience is diametrically different from that in men. We are learning that heart disease and cancer may have more in common than we could have imagined. And we are learning how human evolution itself may have led to the epidemic of heart disease. In understanding how our knowledge of the heart evolved, State of the Heart traces the twisting and turning road that science has taken—filled with potholes and blind turns—all the way back to its very origin.