This course considers the barriers to establishing a defendant's guilt in common law jurisprudence. It is particularly concerned with questions of criminal responsibility and forensics, and with the interaction of medical, social scientific, and legal expertise in criminal contexts. The focus throughout is on the mind: How do we distinguish between disease and depravity, truthtelling and lies, bad luck and bad character? What kinds of technologies and expertise do we rely on to make these determinations? Common law jurisdictions have placed issues of mental capacity and culpability at the centre of their criminal justice systems. From assessing a defendant's fitness to plead to the criminal trial, from sentencing to evaluating a prisoner's eligibility for parole, the quality of a person's mind, and our ability to know it, is essential. This course approaches the concept of the 'guilty mind' from a critical perspective, emphasizing the roles of culture, context, and history in informing our understandings of the self, moral agency, and sinfulness. The reading list privileges historical, literary, and sociolegal works, especially monographs. These are paired with legal and policy-oriented articles that help us to bridge the gap between the past and the present, and to consider how recent developments in psychology and neuroscience affect how we approach the criminal mind today.