The chapter lays the groundwork about the mind and causation. It characterizes theories about the nature of mind: physicalism, particularly non-reductive physicalism, and dualism, particularly naturalistic dualism. It then turns to causation, its relata, and counterfactual conditionals, the claims that express difference-making. Counterfactual conditionals, their general truth-conditions and logical relations are introduced, as are issues about how to evaluate them. A principle about causation in terms of counterfactual conditionals is defended that is crucial for later arguments. According to this principle, an event causes a later event if the later event would not have occurred had the first event not occurred. Although plausible, the principle needs refinement to deal with some prima facie difficulties. Assumptions need to be made about how to evaluate counterfactual conditionals like ‘If the first event had not occurred, then the second event would not have occurred’. Rival views about causation in terms of transference conflict with the counterfactual principle in so-called cases of double prevention. The conflict should be resolved in favour of the counterfactual principle.