In patients with coronary artery disease, surgical revascu- larization with arterial or venous bypass grafts not only relieves symptoms, but also prolongs life. The result of such interventions, however, is frequently impaired by graft dysfunction and occlusion. This monograph highlights the clinical importance of coronary artery bypass graft disease and, in particular, the use of modern diagnostic techniques to assess graft structure and function. The molecular and cellular mechanisms of coronary bypass graft disease are ex- tensively discussed with several chapters devoted to prophy- lactic medical therapy. The indication, technique and results of reinterventions with balloon angioplasty, reope- ration or transplantation in patients with graft failure are also reviewed.