Any theory of explanation must capture the intimate connection between explanation and causation, or between explanation and a broader notion of dependence, which includes causal and, e.g., mereological dependence. This does not, however, require realism about causation. Following up on a suggestion of P. Kitcher's, I analyze causation in terms of explanation. In order to recover a relation of causation from an augmented and improved version of Kitcher's theory, I develop a notion of an ideal historical explanation: A is causally relevant to B just in case A and B are distinct events and there is an ideal historical explanation for B that makes essential reference to A. The unificatory structure of explanation is crucial to generating a ...