The period between the French Revolution and the Second World War saw an unprecedented proliferation of mapmaking and map reading across modern European society. This book explores the “age of cartophilia” through the story of mapmaking in the disputed French-German borderland of Alsace-Lorraine. During the nineteenth and twentieth centuries, French and Germans claimed Alsace-Lorraine as part of their national territories, fighting several bloody wars with each other that resulted in four changes to the borderland’s nationality. In the process, the contested territory became a mapmaker’s laboratory, a place subjected to multiple visual interpretations and competing topographies. The cartographers that mapped Alsace-Lorraine at the height of its nationalist conflict were not the people that we might expect. When we typically think of a border surveyor, we picture a man in a military uniform positioning border markers onto land with the help of scientific instruments. Cartophilia challenges this stereotypical image of a border surveyor. It demonstrates that Alsace-Lorraine’s mapmakers were people from all walks of life, including linguists, ethnographers, historians, priests, and schoolteachers. Empowered by their access to affordable new printing technologies and motivated by patriotic ideals, these “popular mapmakers” re-defined the meaning and purpose of European borders during the age of nationalism.