Criminal law has struggled to keep pace with developments in psychiatry, both in substantive and procedural terms, and it is widely recognised that increased inter-disciplinary discussion of mental condition defences is required in order to address this gap between the law and psychiatry. This edited collection comes at a time of review of this sensitive area of criminal law. The Law Commission for England and Wales recently placed its evaluation of insanity, automatism and intoxication on hold, while it considers the law on unfitness to plead. These reviews are set against the backdrop of earlier Law Commission reports on partial defences to murder which informed significant changes that were made to the law in this area under sections 52–56 of the Coroners and Justice Act 2009. Recent developments in case law in this substantive area illustrate not only the importance of the role of the medical expert, but also that reform in this area is informed by ongoing inter-disciplinary research. This collection brings together medical and legal conceptions of mental disorder in order to appraise the operation of mental condition defences. In this respect, it provides invaluable and original insights into mental condition defences and criminal law.