Historians work with sources that are products of specific social, cultural, political, and economic contexts. Thus, understanding how and why sources were produced and why they survived is an essential component of historical scholarship. At the same time, many historians often employ some sort of conceptual framework—implicit or explicit, descriptive or normative—in order to translate the sources into a coherent narrative. Modern economic historians are no different. The sources tend to be quantitative and focused on economic phenomena (with many exceptions), but doing economic history well means interrogating the origins, trustworthiness, and usefulness of the data in question. In doing this, modern economic historians are largely unapologetic about employing the tools—especially statistical—and intellectual apparatus of economics to interrogate their sources, much as social, political, or environmental historians draw on ideas and methods from related disciplines in their own inquiries. This is precisely how we make sense of the historical process of economic development.