Around the turn of the nineteenth century, states within the German language area passed groundbreaking laws against the unauthorized reprinting of books. The authorial rights reforms that swept the region prompted fierce disagreements over concepts such as authorship, piracy and reprinting. How should these terms be defined and implemented? What was an author? How did authorship differ from piracy? Who wielded the power to define the difference? The questions raised by the reform wave echo in current debates about piracy, authorial rights, and intellectual property. This book explores the history of these controversies with the aim of rethinking German print piracy in the early nineteenth century, a period when unauthorized reprinting is believed to have disappeared from the German language area. Against the view a German age of piracy came to an end in the early nineteenth century, this dissertation portrays the size of the German reprinting industry as a contentious matter. Was the German language area on the cusp of an anarchic infestation of piratical book merchants, the historical actors asked? Or had the forces of modernization already purged the book market from disreputable publications? In these discussions, the meaning of words mattered greatly. Those who could assume the authority to define terms such as authorship and unauthorized reprinting also wielded the power to determine whether piratical books had vanished from the German book market. Jens Eriksson is a teacher and researcher at the Department for the History of Science and Ideas at Uppsala University, Sweden. This is his dissertation.