Metaphysics and the theory of knowledge lie at the heart of the Western philosophical tradition, and yet they are notoriously tricky subjects to engage. In this book, Jack Crumley makes those difficult topics intelligible, not only introducing the central issues and arguments but also explaining their broader significance, thereby connecting abstract themes to more familiar concerns. Though topically organized, the book integrates positions and examples from the history of philosophy. Plato, Descartes, and Leibniz are discussed alongside Quine, Kripke, and other 20th- and 21st- century figures. The book's first half examines such key issues in the theory of knowledge such as skepticism, a priori knowledge, and the nature of justification, as well as naturalized and feminist epistemology. A range of metaphysical topics are then explored, including perception, the relationship between body and mind, personal identity, free will, and the existence and nature of God. Peripheral ideas and related historical asides are offered in boxes interspersed throughout the text, providing further depth without disrupting the author's lucid explanations of central themes. Each chapter is written to stand on its own, allowing the reader to proceed directly to whichever topics are of greatest interest.