In this challenging collection of new essays, leading philosophers and criminal lawyers from the United States, the United Kingdom, and Canada break with the tradition of treating the philosophical foundations of criminal law as an adjunct to the study of punishment. Focusing clearly on the central issues of moral luck, mistake, and mental illness, this volume aims to reorient the study of criminal law. In the process of retrieving valuable material from traditional law classifications, the contributors break down false associations, reveal hidden truths, and establish new patterns of thought. Their always illuminating and sometimes startling conclusions makes this essential reading for all those interested in the philosophy of criminal law.