David Waldron Smithers was, among other things, a physician and a pioneer of cancer radiotherapy and a well-respected figure in British medicine and public health. From the 1940s until his retirement from medical practice in 1973, he was the director of the Radiotherapy Department at the Royal Marsden Hospital and London University Chair of Radiotherapy at the Institute of Cancer Research. Using massive amounts of clinical observations, which he interpreted from an organicist viewpoint, and his impressive synthetic thinking, he proposed (...) a coherent alternative perspective to the somatic mutation theory (SMT) which was then, and still is, the dominant theory of cancer. The purpose of this essay is to acquaint the modern audience with his seminal paper, published in 1962, because it deserves to be recognized as a true classic. In it, he examined the lack of fit between clinical observations and the SMT and proposed the rejection of this reductionist perspective. In addition, he built an organicist alternative in which carcinogenesis is seen as a problem of biological organization. His conceptual contribution to the cancer problem has inspired us and other authors over the last two decades. His essay “Cancer: An Attack on Cytologism,” originally published in The Lancet in 1962, is available as supplementary material in the online version of this article. (shrink)