Why does a wine glass break when you drop it, whereas a steel goblet does not? The answer may seem obvious: glass, unlike steel, is fragile. This is an explanation in terms of a power or disposition: the glass breaks because it possesses a particular power, namely fragility. Seemingly simple, such intrinsic dispositions or powers have fascinated philosophers for centuries. A power's central task is explaining why a thing changes in the ways that it does, rather than in other ways: powers should explain why an acorn turns into an oak tree, not a sunflower, or why fire burns wood, and wood can catch fire. This volume examines the twists and turns of the fascinating history of a difficult philosophical concept, focusing on the metaphysical sense of "powers"--that is, the powers that are invoked in the explanation of natural changes and activities. Scholars probe the views of thinkers from antiquity to the present day: Anaxagoras, Plato, the Stoics, Abelard, Anselm, Henry of Ghent, Gottfried Wilhelm Leibniz, Margaret Cavendish, Mary Shepherd, Immanuel Kant, Georg Wilhelm Friedrich Hegel, and numerous others. In addition, the volume contains four short reflection essays that examine the concept of powers from the perspective of disciplines other than philosophy, namely history of music, West African religions, history of chemistry, and history of art. The history of philosophy brims with controversies surrounding the concept of power, and these controversies have not diminished--particularly as potentialities or powers see a revival in contemporary analytic metaphysics. Hence, telling the history of philosophical theories of powers means exploring the trajectory of a concept whose importance to the past and present of philosophy can hardly be overstated.