Throughout the 1960s and 1970s, a dialogue between neurologists and epidemiologists was initiated in Italy, which has resulted in an improvement in the quality of epidemiologic studies of nervous system disorders. At the beginning of the 1980s the Italian Society of Neurology established a Neuroepidemiology Section, after many young neurologists from all regions of Italy had repeatedly stressed the importance of the epidemiologic approach in designing and conducting surveys, and also in acquiring the knowledge and experience that must be applied to methodology in neurologic research. Since that time, neuroepidemiology has been officially recognized as a discipline within neuroscience. Neuroepidemiologic teachings on frequency, etiology, natural history, prognosis, therapeutic approach, etc. for diseases of the nervous system has considerably enriched the experience of Italian neurologists.1 In February 1982, during the 3rd National Congress of the Neuroepidemiology Section of the Italian Society of Neurology, a panel discussion on the epidemiology of multiple sclerosis (MS) was held. This was conducted in response to the great interest in this disease shown by many neurologists following a previous national census of epidemiologic studies in neurology conducted by the Neuroepidemiology Section a year earlier.2 During the Congress a round table on MS epidemiology was organized, and etiologic hypotheses currently considered were discussed.3-9 It became clear during these discussions that a case-control study would be both opportune and feasible. An Italian multicenter case-control study was the natural choice. This design was chosen because MS is a rare disease for which several important etiopathogenetic hypotheses verifiable from anamnestic information have been advanced. Moreover, a case-control study was believed to be the only practical design for a disease expected to have an unknown latency period. During a subsequent meeting included in the program of the Congress of the Italian Society of Neurology in Sorrento, November 1982, …