Mele's ultimate purpose in this book is to help readers think more clearly about free will. He identifies and makes vivid the most important conceptual obstacles to justified belief in the existence of free will and meets them head on. Mele clarifies the central issue in the philosophical debate about free will and moral responsibility, criticizes various influential contemporary theories about free will, and develops two overlapping conceptions of free will - one for readers who are convinced that free will is incompatible with determinism (incompatibilists), and the other for readers who are convinced of the opposite (compatibilists). Mele's theory offers an original perspective on an important problem and will garner the attention of anyone interested in the debate on free will.