The PhD thesis studies the bordering of Europe by attending to the everyday conceptualisations and practices of border officials who enforce state borders in the realm of the European Union, specifically in relation to Schengen regulations and legislation. Based on fieldwork, the dissertation studies how the border officials interpret, perform and transform ‘Europe’s borders’ in their everyday attempts to ensure safe and efficient borders. The end of the Cold War marked a point of acceleration for closer cooperation regarding the management of both territory and mobility between European countries. Such closer cooperation involved a range of ‘alterings’ (Green 2013) of border enforcement. Taking as the object of study the alterations that such closer cooperation initiated, I examine the training of border personnel, the allocation of resources, everyday compromises as well as understandings of how to ensure cooperation and transformation. The thesis is based on field research conducted amongst officials who work with borders within the Schengen Area and the European Union, primarily officers from the Danish police and the European Union Border Assistance Mission to Moldova and Ukraine (EUBAM). The material consists of interviews with border officials and experts as well as participant observations of their diverse working situations, as well as analysis of internal documents,reports, promotional publications, archival material, and news articles. By exploring how the aspirations of transformation and cooperation come to matter amongst border officials, the analytical chapters study the borders of Europe, which emerge through the continual attempts to stabilise and pin down the borders’ location and purpose. The analyses show the contradictory, yet coexisting aspirations that together make up the ‘borders of Europe’. Based on these analyses, the dissertation suggest that future research develop the skill to analytically capture the contradictions and differences in the European project.