This book owes its origins and inspiration to Paul Finn, former Justice of the Federal Court of Australia. Paul suggested, too many years ago, that accessory liability was one of the last great unexplored areas of private law and was worthy of deeper analysis. He was undoubtedly correct in his view. The size and complexity of the topic made us initially reluctant to take on the task, although we individually wrote and researched on various aspects of accessory liability. This convinced us even more of the merit of Paul's idea and we decided to take up his challenge. This book is our attempt to do so. Our many citations of Paul's judgments and academic scholarship throughout the book demonstrate his leadership in this area of law. We are honoured that he has agreed to write the Foreword.

We hope that this book does not disappoint in seeking to meet the challenge of exploring accessory liability (and its boundaries) in its many guises, but we are mindful that we have, perhaps, taken on a far larger task than we initially envisaged. Not only have we sought to explore accessory liability across a range of topics in private law, we have also considered accessory-related doctrines and criminal law; nor have we ignored statutory accessory liability. Further, the book ranges across a number of common law jurisdictions, although the focus is on English and Australian law. Although we took primary responsibility for some of the chapters, the book is the result of our joint efforts. Joachim took primary responsibility for Chapters 4–6 and 9–10. Pauline took primary responsibility for Chapters 7–8. Fortunately, despite robustly criticising each other's writing and methodology and arguing at length over our ideas, we have remained good friends.

This book could not have been achieved without the assistance of many people. We are grateful to those who have given up their time and been happy to share their wisdom. We apologise to anyone that we may have overlooked in the note of thanks here.

First, we would like to thank the friends and colleagues who have read parts of the draft manuscript and/or discussed our ideas with us.