Despite their crucial importance for defining a subject, concepts often receive only little attention in historical research projects. While the lessons on conceptual change learnt from scholars such as Koselleck and Skinner have resulted in the establishment of an entire subfield of conceptual history, many historians working on politics in practice are easily tempted to leave conceptual reflections entirely to these specialists. Yet, it is hard to imagine research projects in political history that do not in one or another way engage with concepts such as power, violence, rule of law, institutions, identity, colony, democracy, ideology, representation etc. PhDs working on international topics, like the history of international relations, often do work with concepts, often borrowed from the social sciences. In this tutorial, we will briefly introduce you to the various ways in which both historians and social scientists deal with the challenge to define and/or reflect upon their central concepts, and invite you to reflect upon the concepts central to your research project.