Initial pioneering efforts of direct coronary artery bypass were all performed on a beating heart. Although originally introduced into cardiac surgery for the repair of intracardiac defects, the ability of John Gibbon's heart-lung machine to create a motionless, bloodless operative field catalyzed coronary artery bypass surgery. During the ensuing decades tens of millions of patients benefited from coronary revascularization on cardiopulmonary bypass. As we celebrate the 50th anniversary of the invention of the heart-lung machine the landscape of interventional treatment of coronary artery disease has shifted dramatically. Although instrumental in the genesis of the field of coronary revascularization, the role of the heart-lung machine has now diminished. Two thirds of all coronary revascularization is now performed by percutaneous approaches and one fourth of all coronary artery bypass grafting procedures are performed without the heart-lung machine. However owing to the complexity of patients now requiring revascularization as well as recently introduced incremental improvements to cardiopulmonary bypass including coated, low prime circuits, closed integrated systems, and pharmacologic adjuncts Gibbon's heart-lung machine will continue to play an integral role in this field. (C) 2003 by The Society of Thoracic Surgeons.