In most parts of psychology, theory-building aims at general propositions and law-like formulations that, in the sense of the old Greek ideal of Truth, are not subject to the vagaries of time and place. As soon as theories are accepted by the scientific community and receive a place in textbooks, they become decontextualized or, a-historical. Only the names of the authors remind us of their origin: for example, the James-Lange theory of emotions, Pavlov's conditioned reflex theory, Festinger's cognitive-dissonance theory, and so forth. My contribution to this symposium consists of a plea for recontextualization of theory as an important contribution of the history of psychology to theoretical psychology. This means a rehabilitation of the context of discovery, which in current philosophy of science is relegated to the psychology of creativity and the curiosity-shop of biography. I will try to show that a contextual analysis, in which the original problem situation is reconstructed, does not necessarily lead to relativism and resignation, but also can help us to assess the contribution of past theoretical ideas to current theoretical discussion. Progress in science thus is furthered by historical regression.