A research project undertaken at the Geographical Institute, University of Berne, analyzed the demographic development in the European Alps between 1870 and 1990 at the level of the commune. Studies of growth, stagnation, decline, commune size, and altitude in almost 6,000 communes are presented on three colored maps enclosed with this issue. It is apparent that two highly divergent processes are at work and, accordingly, statistical mean values reveal little of importance. Approximately one-half of Alpine Europe is undergoing general economic and demographic growth and has experienced significant increase in population since the end of the agricultural era. This development has taken place primarily in low-lying valleys and basins and in areas bordering the Alps that have good access to transport routes. Tourism is not as widespread as generally assumed and is usually characterized by a punctate pattern. Only in the western part of the Eastern Alps does tourism account for widespread population growth at higher altitudes; elsewhere the Alps have not been affected by modern development and the economy and population are declining, with some areas in danger of becoming completely abandoned. The results challenge the earlier concept of the Alps as a rural region, once populated by peasants, where tourism now plays a major role. The structural change relates to ecological, social, cultural, and economic problems, and region-specific mountain policies should be introduced.