Historical actors are as central to the history of knowledge as to all historical scholarship. Every country, every era has its biographies of eminent scientists, intellectuals, and educational reformers. Yet the theoretical currents that have left their mark on the historical and sociological studies of knowledge since the 1960s have emphasized structures over actors, collectives over individuals. By contrast, Knowledge Actors stresses the importance of historical actors and re-engages with their actions from fresh perspectives. The objective of this volume is thus to foster a larger discussion among historians of knowledge about the role of knowledge actors. Do we want individuals and networks to take centre stage in our research narratives? And if so, which ones do we want to highlight and how are we to conduct our research? What are the potential pitfalls of pursuing that actor-centric trajectory? This the third volume in a trilogy about the history of knowledge from the Lund Centre for the History of Knowledge (LUCK).