The chapter begins with antecedents. These include those of the German philological tradition, then Max M� Ratzel, and others, before the British twentieth-century diffusionists, Elliot Smith and Perry. After this came the culture-area theorists, including Wissler, and then the regional approaches of ‘Dutch structuralism’. The chapter highlights the complexity of these schools and ends with a consideration of three types of comparison: illustrative, global-sample, and controlled.

While regional comparison’s methodological relevance is diminishing, its significance for historical anthropology may increase if properly assessed and reconfigured. This chapter argues this point by discussing three examples from historical South Arabia. These cases highlight the significance of adequately reflecting and identifying existing notions of the “regional” in any given research context as the basic frame of reference in this version of comparison. As a crucial device from science studies and critical theory, the distinction between contexts of discovery, of justification, and of application may be useful for a reliable yet open and flexible conceptualization that includes self-reflexive as well as indigenous notions of the regional. It is also suggested that regional comparison can be improved by triangulating it with other methodological devices, ranging from network analysis to medium-range insights from general anthropology. In turn, this may advance the operational usefulness of regional comparison in historical anthropology by strengthening its potential for highlighting both regional commonalities and diversities among the phenomena under scrutiny.

While ethnography produces highly contextualized understandings of fields of practice, it is hard to assess whether the phenomena revealed through ethnographic study are typical on a regional level. To overcome this shortcoming, I introduce a research design, ethnographic upscaling, that combines in-depth ethnography with larger-N regional comparisons. While the in-depth ethnography provides valid hypotheses, comparison allows the testing of whether an observed phenomenon can be generalized. To illustrate ethnographic upscaling, I present research on the social engineering of water governance in Namibia. In the course of political “decentralization,” and inspired by community-based natural resource management policies, pastoralists have developed new rules stipulating how to share water and distribute the costs of providing it. While all communities were exposed to similar blueprints, local social practices concerning water governance differ. I show that these variations can be explained if we combine an ethnographic understanding of the dynamics within communities with an understanding of both networks that impinge on the individual cases and influences of external authorities.