This Element presents the main attempts to account for causation as a metaphysical concept, in terms of 1) regularities and laws of nature, 2) conditional probabilities and Bayes nets, 3) necessitation between universals and causal powers, 4) counterfactual dependence, 5) interventions and causal models, and 6) processes and mechanisms. None of these accounts can provide a complete reductive analysis. However, some provide the means to distinguish several useful concepts of causation, such as total cause, contributing cause, direct and indirect cause, and actual cause. Moreover, some of these accounts can be construed so as to complement each other. The last part presents some contemporary debates: on the relation between grounding and causation, eliminativism with respect to causation in physics, the challenge against 'downward' causation from the Closure and Exclusion principles, robust and proportional causation, and degrees of causation. This title is also available as Open Access on Cambridge Core.