In black economic history, as in any history, the facts do not speak for themselves. They require selection, classification, and interpretation, and for these purposes the investigator must employ a model. That any attempt at causal analysis must make use of a model, either explicitly or implicitly, is generally admitted. That explicit models are preferable to implicit ones is a long-standing precept of economists and a principle increasingly affirmed by historians. But recognition of the need for an explicit model is only a starting point. Real difficulty arises in choosing an appropriate model. The economic historian, generally a consumer rather than a producer of models, can look to the economic theorist for assistance. The historian may not find exactly what he needs in the existing corpus of economic theory, but it is nevertheless a good place to begin the search for an appropriate model.