This Part brings together the threads from Parts I, II and III to explore what patterns of development we can identify, understand and compare across legal systems (Chapter 9) and concludes with some brief reflections on what we have learnt about the relationship between tort law and criminal law (Chapter 10). Part I’s methodology is a key background to understanding the interactions highlighted in this Part. For example, we see the importance of demarcating domains of study: Part II explained the generally low levels of interaction despite the terminological and functional overlap of tort and crime fault doctrines, while Part III showed how strong interactions on a procedural level might be, at specific points in time. We have also seen the axes of Hierarchy/Equality, Partition/Porosity and Iin/Directness in how the two areas have interacted or not interacted.