In this "nation of associations," organizations are frequently established to serve the common interests of their constituencies. The periodic emergence of associations serving the neurosurgical community is a matter of historical record. However, little attention has been paid to the reasons why these neurosurgical associations have come into being. Because little has been published documenting the developmental phases of these associations, the research for this study has concentrated on the personal correspondence of the founders, as well as on the minutes and the historical records of the organizations themselves. The results demonstrate a definite pattern in the sequence of events that has led to the establishment of five national neurosurgical organizations over the past 75 years. All of them were designed to pursue the same general goals. Yet, each was conceived by its designers to fulfill unmet needs of the surgeons that it was established to represent. It is postulated that the definable pattern of these events provides a sound basis for predicting a reoccurrence of the phenomenon in the future. The conspicuous absence of several prominent academic and research societies from these discussions is not meant to reflect upon the value of these organizations to their respective constituencies. This study is limited to the evolutionary "chain" of organizations devoted to the specialty as a whole, which have, to one extent or another, played a part in the development of policies and activities that have influenced the neurosurgical specialty since its inception. Other national, regional, and special interest societies continue to serve defined elements of the specialty and could be the subject of a similar historical summary.