This chapter takes up the story of the development of criminal responsibility in Australian criminal laws in the last decades of the twentieth century. At this point, a number of currents running through the century – including modernisation, codification and the coherence of Australian criminal laws – which are discussed in preceding chapters of this book, come together. This period represents the high-water mark of faith in the value and feasibility of organising criminal law around criminal responsibility, as legal and other changes occurring on the national and international levels were met with an attempt to fix criminal responsibility principles at the heart of Australian criminal law. As I show in this chapter, in this period, criminal responsibility became key to the self-definition of the criminal law, and the language of criminal responsibility became the language of the criminal law.