I characterize a notion of causal agency that is the causitive component of many transitive verbs. The agency of what I call substantial causes relates objects physically to systems with which they interact. Such agent causation does not reduce to conditionship relations, nor does it cease to play a role in scientific discourse. I argue, contrary to regularity theories, that causal claims do not in general depend for their sense on generalities nor do they entail the existence of laws. Clarification (...) of the relationships among substantial causes, causal processes, and explanatory conditions separates the analysis of causal connection from that of nomological connection. This clarification is then applied to a variety of issues in the analysis of causality. (shrink)