Elise Bant

Unjust enrichment is one of the least understood of the major branches of private law. This book builds on the 2006 work by the same authors, which examined the developing law of unjust enrichment in Australia. The refinement of the authors' thinking, responding to novel issues and circumstances that have arisen in the maturing case law, has required many chapters of the book to be completely rewritten. The scope of the book is also much broader. It concerns the principles of the law of unjust enrichment in Australia, New Zealand, England and Canada. Major decisions of the highest courts of these jurisdictions in the last decade provide a fertile basis for examining the underlying principles and foundations of this subject. The book uses the leading cases, particularly in England and Australia, to distil and explain the fundamental principles of this branch of private law. The cases discussed are current as of 1 May 2016 although the most recent could only be included in footnotes.

This book defines and explains the operation of the defence of change of position in Anglo-Australian law. It is a widely accepted view that the defence is a modern development, the first express recognition of which can be traced in England to the seminal decision of the House of Lords in Lipkin Gorman (a firm) v Karpnale Ltd. Commentators have accordingly tended to focus on post-Lipkin case law in discussing the defence and its many disputed features. This work takes a different stance, arguing that the defence is best understood by placing it within its broader historical and legal context. It explains that the foundations of the defence can be found in the related doctrines of estoppel by representation, the agent's defence of payment over and the law of rescission. The analysis applies crucial insights from those areas, together with the change of position authorities and broader considerations of policy and principle, to develop a rigorous model of the change of position defence. The work not only provides a clear and exhaustive examination of the defence, but demonstrates that, properly understood, the defence operates in a rational and justifiable manner within its broader private law context. In so doing, its analysis meets the oft-expressed concern than the defence may operate in an unprincipled way or by reference to 'that vague jurisprudence which is sometimes attractively styled "justice as between man and man"'.

Unjust Enrichment in Australia contains a comprehensive summary and analysis of the case and statute law on unjust enrichment in Australia. It is presented in a way which is designed to be easily accessible for students and practitioners who are not familiar with the area and it engages in discussion of many of the immensely difficult issues of theory that lie beneath the surface in this area of rapidly developing law.