This volume is a selection of essays taken from the excellent range of papers presented at the British Legal History Conference hosted by the Institute for Legal and Constitutional Research at the University of St Andrews, 10–13 July 2019. The theme of the conference gives this book its title: ‘comparative legal history’. The topic came easily to the organisers because of their association with the St Andrews-based European Research Council Advanced grant project ‘Civil law, common law, customary law: consonance, divergence and transformation in Western Europe from the late eleventh to the thirteenth centuries’. But the chosen topic was also connected to the fact that this was, we think, the first British Legal History Conference held at a university without a Law faculty. Bearing in mind the question of how far institutional setting determines approach, our hope was that an element of fruitful comparison would stimulate people to think further about the range of approaches to legal history. With its explicit agenda of breaking down barriers, comparative legal history provided a particularly suitable focus for this investigation. After situating the subject matter of comparative legal history, and then discussing the levels of comparison that may be most fertile, this introduction moves on to considering the practical tasks of researching and writing such history, using the essays included in the volume to suggest ways ahead. The introduction groups the essays under certain headings: ‘Exploring legal transplants’; ‘Investigating broader geographical areas’; ‘Case law, precedent and relationships between legal systems’; and ‘Exploring past comparativists and the challenges of writing comparative legal history’. Yet the essays could be kaleidoscopically rearranged under many headings. We hope that the book, like a successful conference, includes many stimulating conversations.