Book excerpt: The difficulties of exploring African history, especially for earlier periods, have spurred the development of a wide range of methodologies and approaches, such that Wyatt McGaffey once termed it "the decathlon of the social sciences." Historians have long utilized archaeology, ethnography, historical linguistics, and oral traditions in their study of the continent, but are only beginning to explore the possibilities of genetics or many of the techniques used by modern archaeology and other emerging sciences. And as digital sources-from historical documents and statistics to cartographic, climatic, demographic, and environmental modeling-proliferate, so do the problems in using them. The Oxford Encyclopedia of African Historiography: Methods and Sources examines how these developments have influenced the scholarship that historians produce. Such methods continue to evolve, demanding that historians develop basic understandings of them. Thus, the two-volume Encyclopedia builds a theoretical foundation for the field, expanding the ways that Africa can be studied, and recovering the histories of the continent that often appear outside of the documentary record.