The tone for this excellent book is set by an elegant, thoughtful Foreword by the author of the first edition, and the second edition's namesake, Francis Gurry. As he points out, since the first edition was published in 1984, a technological revolution has fundamentally changed the way information is created, communicated and stored. Creating a coherent and accessible account of how the law has developed during that 28 year period is a therefore an ambitious undertaking. As he acknowledges, the authors of this second edition – two academics and two practising barristers – rise to the task admirably.

As a testament to the enduring value of Gurry's work, the structure of the second edition echoes that of the first. Inevitably though, this edition is much longer including Part I which contextualises in welcome detail the discussion that follows. The authors, led here by Professor Bently, begin by explaining the role played by breach of confidence in the protection of commercially valuable ideas, state secrets, and private life and in the determination of immunity from many obligations of disclosure. They then provide a detailed history of the action, establishing persuasively that the protection of confidence was embedded in English law well before Prince Albert v Strange (1849) 2 De G & SM 652; 1 Mac & G 25; 1 H & Tw 1; was decided. The authors then consider the various philosophical bases for the protection of confidence, concluding, however, that none is entirely satisfactory. Part II, led by Professor Aplin, also examines an important foundational question; the jurisdictional basis of the action. A clear conclusion on this difficult issue is reached: the authors submit, consistently with the first edition, that the “policy of the law” is the basis of the courts' jurisdiction and that the jurisdictional sources on which the courts rely are secondary mechanisms by which that policy is enforced. In other words, the action is sui generis.

Parts III and IV, led in the main by Professor Aplin, form the heart of the book. In Part III, the authors identify the principles which determine when information will be “confidential”. They look, first, at the general characteristics of the requirement of “inaccessibility” and, then, at how that requirement is applied to trade secrets, artistic and literary information, government secrets, and personal information. The rationale for this categorical approach is clearly explained. Whilst inaccessibility is the fundamental attribute of confidential information, its existence, the authors say, is determined by reference to the different policy considerations underlying each category. The exception, they argue, is personal information: in this context, harm, not inaccessibility, is now the touchstone. In Part IV, the scope of the obligation of confidence is explored. Here, the authors identify a central, unifying test for identifying non-contractual obligations of confidence: namely, whether the circumstances in which the information was acquired or received indicate objective knowledge or notice that the information was confidential. They then show that this test explains the imposition of obligations of confidence across the board – where information is voluntarily disclosed by confider to confidant, when it is obtained accidentally, surreptitiously or by a third party, and where the private/personal information is involved. This important conclusion provides a strong foundation for the discussion which follows and, indeed, for understanding the English law of confidence as a whole.

Next comes an insightful discussion, led by Professor Bently, of breach of confidence in employment relations and relations with the state. As in the first edition, analysis of the first of these topics is divided into obligations arising during and after employment. Policy arguments underpinning workplace confidentiality are closely scrutinised. In particular, the book acknowledges the changed nature of the employment relationship and the increasing recognition of the role of mobile, skilled workforce in promoting innovation. These observations then inform a thoughtful critique of the case law, particularly of the application of the restraint of trade doctrine. Policy tensions are also identified at the outset of the discussion – in Part VI – of the state's obligations in respect of confidential information it holds about individuals and institutions. The authors recognise that the government's need to protect confidentiality can conflict with the public's desire for transparency and, conversely, that the need to protect individual privacy can undermine governmental attempts to share data efficiently. Having set out the complex melée of rules currently designed to negotiate these tensions, the authors devise a workable means of rationalising both the state's obligations and freedom of information regimes.

Parts VII and VIII, led by Simon Malynicz, address the duration of obligations of confidence, breach of those obligations, and defences to the breach of confidence action. Discussion of the latter is appropriately divided into two sections: the first articulates defences to “traditional” breach of confidence (including danger to the public, wider community interests, and “putting the record straight”) and the second identifies factors which bear on the balance struck in privacy cases between the European Convention rights to respect to private life and to freedom of expression. This is followed by a practical, detailed articulation of the remedies available to claimants. This includes helpful explanations of the differences between equitable and common law remedies and of the jurisdictional bases for each. Finally, Part X (which, like Part IX, is led by Phillip Johnson) sets out clearly the treatment of confidential information in public and private international law explaining, for example, the relevance of the Trade Related Aspects of Intellectual Property Rights and Anti-Counterfeiting Trade agreements and the likely application of jurisdiction and choice of law principles in this context.

As this partial summary is designed to demonstrate, one of the book's key strengths is the breadth of coverage. All aspects of the law of confidence are addressed. The book discusses, in detail, the historical context of the action, general principles, defences, remedies, and the action's operation in the employment, privacy, governmental, and international law context. Each section provides a comprehensive summary of the law in question and soundly-based, insightful views on how the law should develop. The book is therefore an invaluable reference tool for any practitioner, scholar or student. But Gurry on Breach of Confidence is more than a clear and comprehensive articulation of the law. Throughout the book, difficult questions are authoritatively and thoughtfully answered. Particularly in the first six parts, the authors thoroughly interrogate the policy reasons underpinning breach of confidence and identify principles which transcend the different contexts in which they operate. They reach clear conclusions about the fundamental elements of the action – about the centrality of accessibility, the need for objective knowledge of the confidence, the sui generis nature of the action, the conceptual uniqueness of the misuse of private information cases – and then rely on, and develop, those conclusions throughout the work. A consistent, coherent theory of breach of confidence therefore emerges.

In order to achieve this coherence, the authors had to confront, inter alia, two conceptual difficulties: the jurisdictional uncertainty at the heart of the breach of confidence action and the unclear and constantly evolving relationship between “traditional” breach of confidence and the misuse of private information cases decided since enactment of the Human Rights Act 1998 (the “HRA”). As mentioned, the first of these difficulties is resolved by endorsing Francis Gurry's sui generis approach to the breach of confidence action. The second – fitting the HRA-based misuse of private information cases into the breach of confidence taxonomy – is achieved by illustrating when privacy cases fit within general breach of confidence principles and when they do not. For example, the general basis of an obligation of confidence – that the defendant had notice of the confidential nature of the information – is shown to be apposite in both privacy and “traditional” cases. In contrast, the need to balance privacy and freedom of expression interests applies only in the personal information context. The authors also show that Lord Goff's famous extension of the obligation of confidence to information which is adventitiously obtained (in Attorney-General v Guardian Newspapers Ltd [1990] 1 AC 109, 281) has had limited acceptance outside the privacy cases. It follows that, except where breaches of privacy are concerned, breach of confidence is still principally concerned with voluntary communications between a confider and confidant.

These observations are illuminating for those seeking to understand privacy cases in their wider breach of confidence context. They show that guidance is still to be had both from both pre-HRA personal information cases and from the non-privacy, modern breach of confidence action. They also show that, despite radical changes to the protection of personal information, breach of confidence generally continues to operate on traditional principles. As a result, the English law of confidence – and this book's articulation of it – have significant continued relevance for other common law jurisdictions.

It seems niggardly to find any fault with a work of this calibre but it is perhaps worth suggesting that the authors could have taken a stronger position on the philosophical (as opposed to doctrinal) foundations of the breach of confidence action. Although the conclusion that no single rationale explains the action's importance is persuasive, the authors might have explained whether and how, in combination, those rationales provide a sound theoretical foundation for confidence protection. Criticism can also be made of one aspect of the book's production. Although the chapters are divided into labelled parts, subheadings are not numbered. Heading hierarchy is, instead, indicated by use of various combinations of bold type, indenting and italics. Although this is logical in theory, it is somewhat confusing in practice – the reader cannot tell at a glance how a particular section or paragraph fits into the overall discussion. This is particularly problematic if the reader dips into a chapter after using the index.

These are minor matters, however, and there is no question that this book is an immensely valuable addition to the literature. It is highly recommended, therefore, to anyone, either in the United Kingdom or outside, who practises or researches in this fascinating and increasingly important area.