This volume is a collection of papers that advance our understanding of the metaphysics of powers '” properties such as fragility and electric charge. They focus on questions concerning the metaphysics of powers that cut across any particular subject-specific ontological domain -- whether philosophy of science, philosophy of mind, ethics, epistemology ' investigating the metaphysical structure of powers, the nature of the manifestation of powers, the necessity or contingency of a power's relation to its manifestations, and powers and causation.ã