Published on the occasion of Hubert Houben's 70th birthday, this volume focuses on border crossings as one of the topics dear to the jubilarian. By starting from a concept of borders as a social construct, the authors look at selected cases of transcending spatial, cultural and legal boundaries in the Middle Ages. The resulting complexity and multi-perspectivity reflects different research methods and traditions, revealing a broad spectrum of possible approaches to the topic of border crossings.