Narratives of history profoundly shape international relations (IR) scholarship. Periodizations and grand historical narratives are vitally consequential, establishing the very parameters in which IR scholars labor, speculate, and theorize. Therefore, we should be highly attentive to how we produce these narratives. Yet there is a surprising lack of reflection on general practices in such matters. One common method that international relations uses to set these parameters—identify the basic properties of international systems, chart their comparative dynamics, and construct periodizations and grand narratives of history—is to begin with an initial focus on the predominating units, unit types, and/or regime types present in the global system at any given point in time. Dynastic families, states, city-states, empires, democracies, and autocracies—all have had ideal-typical worlds of relations constructed around them. This “unit approach” is important in making behavioral arguments about actors in international relations and is especially interested in how it has been and can be used to construct improved narratives of IR history that liberate us from the “Waltzian hangover” of a dysfunctionally simple account of history. The three main versions of the unit approach are based on unit type, state type, and regime type. This paper makes arguments about the appropriateness of a unit approach to historical narrative construction and its advantages over other approaches, such as structure-oriented developments.