In many regions of Europe and beyond fortifications belong to the most impressive of archaeological remains. Their study has a long tradition and today a multitude of aspects about architecture, function or symbolism has been explored. However, fortifications are generally examined in a temporally, regionally or culturally limited context. Going a step further, this volume aims to bring into focus concepts of fortifications, which can be socially, symbolically or functionally, but also chronologically and supra-regionally aligned. An important question is to determine which fortification elements are culture-specific, and which can be regarded as convergence or even universal phenomena. Adopting a comparative view, the central aim of the volume is to highlight the diversity and the structural similarities of ancient fortifications. The chronological framework goes from the Neolithic to the Late Iron Age, and the geographical scope from the Ural steppes to the Iberian Peninsula.