The development of the concept of pain and its treatment constitutes one of the most interesting and fascinating chapters in the history of medicine. The concept proposed by Aristotle and other ancient Greek philosophers that pain was a passion of the soul remained widely accepted for some 22 centuries, and treatment remained empirical and often ineffective. For a century after the scientific study of pain began, several theories were proposed, and these theories prompted the development of various therapeutic modalities. However, until two decades ago, pain research remained conceptually stagnant; the meager work done was not commensurate with the magnitude and clinical importance of pain. Consequently, pain treatment remained somewhat empirical and ineffective. Whatever knowledge and effective therapeutic modalities were available were not properly applied, primarily because medical students and physicians were not taught the basic principles of pain management. Fortunately, during the past two decades, significant advances have been made in our knowledge of basic mechanisms and a variety of new modalities have been introduced and old ones refined. Although we should be proud of these advances, much more needs to be done if the millions of patients with acute and chronic pain are to be managed effectively. This requires sustaining and expanding research programs; educating and training health professionals; and informing the public.