This paper outlines a conceptual background for understanding the dynamics of metropolitan regions and urban systems in general. An essential part of the paper reviews existing theoretical explanations of urban change processes with special attention being paid to long term cycles and waves as well as discontinuities and qualitative changes in the evolution of metropolitan regions. The paper introduces a distinction between constrained and structural dynamics. With reference to this distinction, the authors describe and classify various forms of urban oscillations and changes in urban structures. Relations between technological development and infrastructural change are also discussed
