This book tells the story of idealism in modern philosophy, from the seventeenth century to the turn of the twenty-first. Guyer and Horstmann discuss many philosophers who have played a role in the development of idealism, including Descartes, Hobbes, Spinoza, Leibniz, Locke, Berkeley, Hume, Kant, Hegel, Schopenhauer, Nietzsche, and Wittgenstein.