1890-1930 was a formative period in the evolution of the modern town planning movement. It was a time when the relationship between social development and the physical environment, in all its complexities, was being explored, and when the prospect of future change could run ahead of the problems of implementation. This study highlights the richness and variety of European responses to modernisation by offering a comparative approach to exploring these themes in cities in Britain, France, Germany, Spain and Central Europe. Of key importance in the development of European cities during this period was the first world war, which accelerated technological changes at the same time as inspiring both nostalgia for the past and a desire to create new ways of urban living. For large provincial cities that had grown in the 19th century, imagining a new future was the greatest challenge. What kind of understanding was necessary to promote effective new developments? How could these be implemented in the face of economic, social and political change? Who made the decisions? Answers to these questions must be drawn from a number of directions: from the political and administrative structures of nation-states; from the economic and social history of Europe; from the growth of new professional expertise in dealing with urban problems and the international exchange of ideas; from the specific histories of cities; and from the actions of individuals who were ultimately responsible for creating new possibilities.