To fully grasp how so many smart, right-minded people could get it so wrong, it might help to start with a quick review of medical history. Take the radical mastectomy, conceived by William Halsted in the late 19th century. The procedure was intended to remove all cancer cells of the breast, the overlying skin, the underlying muscle, and regional lymph nodes (Figure 1). It was mutilating, permanently disfiguring, and no more effective than less radical, less disfiguring procedures. Still, because of the prestige and respect Halsted commanded as a teacher of surgeons, his disciples defended and taught the radical mastectomy at the most revered medical colleges. His extreme surgery was perpetuated for almost a century, until challenges by courageous physicians in Europe and America, along with a prospective randomized study by Dr. Bernard Fisher, finally sounded the death knell of this standardized surgical error of the century ...