Certain body parts occupy a privileged position in culture. The eye, the ear, the hand, the face, the flesh—parts that are visible, instrumental, and experiential—play an outsized role in language, myths, visual images, and sense of self. So do certain body parts that are covered but conspicuous: the brain, the stomach, and especially the heart. In many cultures, the heart signifies selfhood, love, courage, religious rapture, the essential core of things. Hearts pound, break, dry up, open or close, soften or harden. Then there is another history: one that began in Greco-Roman antiquity and quickened in early modern Europe, when the heart became the subject of anatomical and physiological research that in turn led to the achievements of the 20th and 21st centuries, when the heart became the object of audacious and celebrated feats of surgery and other radical medical interventions.