Book excerpt: There were no medical oncologists until a few decades ago. In the early 1960s, not only were there no such specialists, many practitioners regarded the treatment of terminally-ill cancer patients with heroic courses of chemotherapy as highly questionable. Physicians loath to assign patients randomly to competing treatments also expressed their outright opposition to the randomized clinical trials that were then relatively rare. And yet today these trials form the basis of medical oncology. How did such a spectacular change occur? How did medical oncology move from a non-entity and in some regards a reviled practice to the central position it now occupies in modern medicine? Cancer on Trial answers these questions by exploring how practitioners established a new style of practice, at the center of which lies the cancer clinical trial.