The tree of cardiac surgery emerged from seeds that were sown a mere century ago when effective means to manage cardiac trauma and the advent of reliable methods of pulmonary ventilation permitted open-chest operations. Initial successes led to early surgical attempts to correct or palliate “approachable” lesions such as mitral stenosis and patent ductus arteriosus with the heart still beating. The need to stop the heart in order to do more elaborate repairs stimulated seminal work on hypothermia and the landmark development of cardiopulmonary bypass, the two golden keys that opened the door to the remarkable accomplishments of contemporary cardiac surgery, epitomized by cardiac transplantation—severely restricted due to the continued shortage of donor hearts—and intensive efforts to develop a reliable permanent total artificial heart...