The law's treatment of cohabitation has prompted a vast amount of academic scholarship. This is unsurprising as this past decade has seen several Law Commission reform projects, a handful of Private Members' Bills introduced into Parliament and a steady stream of cases highlighting the differing legal treatment of married couples and cohabitants. As a result, academic journals have become saturated with critique and, problematically, much of this critique involves well-worn arguments meandering over well-travelled ground. At first glance, the amount of literature in this area meant that Professor Rebecca Probert faced a challenge when producing The Changing Legal Regulation of Cohabitation: From Fornicators to Family 1600–2010. Nevertheless Probert's work has in fact produced a truly fresh perspective on the legal regulation of cohabitation by adopting a historical investigation of the relationship between law and behaviour.

From the outset, this book should not be mistaken for something it is not. It is not a historical account of why some cohabitants lived together in past centuries. Rather, it is far more ambitious and focuses on setting “the historical record straight” by exploring how the law treated cohabitants from 1600–2010. It is this important interface between law and social practice, whether through the journey of the law prohibiting behaviour to the position of the law potentially influencing behaviour, which is the central focus of study of this book. Another key aim is to debunk many of the myths and misunderstandings as to the nature and extent of cohabitation during this period.

The structure of the book is as follows. In eight substantive chapters, Probert adopts a largely chronological approach to the material. Commencing from an analysis of the punishment of cohabiting couples and the omnipotence of the church courts in this area, the book then moves on to consider the decline of their jurisdiction and the approach to unmarried relationships undertaken by the secular courts. The latter chapters of the book analyse the more modern material stretching from the rather exceptional treatment of “unmarried wives” to developments in the 1950s to curb “living in sin”. They reveal the gradual increase in rights being conferred upon cohabitants yet ultimately reveal what Probert views as ‘limited protection and selective neutrality’. The final chapters question why cohabitation reform has stalled, despite the gradual increase in protections offered to cohabitants.

The arguments advanced in this book are innovative and offer a new understanding. The early chapters are particularly fascinating and provide insight into the performance of penance by those guilty of sexual offences. They reveal that punishment for fornication or the creation of meretricious contracts had a broad reach that caught individuals not necessarily living together which challenges our traditional understanding of cohabitation as being two cohabitants sharing a home. When analysing the secular law from 1770–1900, Probert describes the legal approach as both “laissez-faire, since individuals were left to suffer the consequences of their own actions” and also one that deterred cohabitation outside of marriage. Although Probert acknowledges other factors than the law may affect the rate of cohabitation, the ultimate thesis in these early chapters is that law endeavoured to ensure “that levels of cohabitation remained low”. The later chapters explore the interface between the divorce reforms in the late 1960s and the “common-law marriage” myth that developed in the 1970s. With the clear presence of legal regulation and statutory provisions affecting those in non-formalised relationships, Probert then provides a nuanced understanding of the problems of legislating for cohabitants. Using a historical analysis, support is provided to the need to avoid homogenising cohabitants as a category and also to rigorously question how far legal rights and protections motivate and incentivise the behaviour of individuals in an interpersonal relationship.

There are several aspects of this book that deserve specific mention. Firstly, the range of sources used in this text should be applauded. Probert draws upon a wide range of legal and non-legal sources. In particular, novels, popular music, television programmes and newspaper articles are referenced throughout this text. Probert remarks that this study involved consulting sources ranging from “crumbling original documents to glossy magazines, and from churchwardens' presentments to the entire series of Carry On films”. This use of a broad array of sources naturally opens up the text to non-academic audiences but also is justified owing to the agenda of the book and the way in which myths and societal misconceptions are uniquely prominent in this area. For example, exploring references to common law wives in the popular press is vital when tracing perceptions of cohabitation in society. Furthermore, it is of particular importance owing to the common law marriage myth which is extensively analysed by Probert in chapters five and nine of this book and also elsewhere. Thus, these sources provide a real originality and richness to this text that Probert uses effectively to make legal arguments about law reform. Secondly, the composition of the text is also accessible for non-legal audiences. Probert “stripped out technical legal terminology” in the main body of the text yet provided extensive references for those wanting to analyse the legal framework. This approach, coupled with Probert's engaging writing style, allows for the central thesis of the text to emerge which is coherently argued throughout the text. Thirdly, the personal reflections of the author on the process of researching this text are also thought-provoking and force individuals to confront and reappraise their own understanding of the law's treatment of cohabitation. Probert notes that “the process of research is rather like doing a jigsaw without the picture on the box” and this observation resonates with many misconceptions that are challenged by this text. To give one example, the reformist argument that cohabitation was relatively prevalent before the late twentieth century is found by Probert to be a “complete fiction”.

It is hard to criticise this book seeing as it is comprehensively referenced, analytical and clearly the product of a lengthy period of extensive research. One minor observation is that the conclusion chapter could have been a slightly longer and drawn more extensively upon the findings of the entire period analysed. Although each chapter conclusion was linked together effectively and the primary objectives of the text were clearly met by the author, some of the innovative and original final arguments could have been discussed in more detail. However, this may merely be a matter of personal taste regarding the nature of a conclusion chapter and is in no way intended to detract from the quality of legal analysis present throughout this text.

The Changing Legal Regulation of Cohabitation makes an important contribution to the academic discourse in this area. This scholarly contribution is insightful, detailed and rigorously argued by the author. Furthermore, the book's contribution is also timely in light of the current debate surrounding the granting of statutory rights and remedies to cohabitants upon relationship breakdown. Therefore, within the specific field of the legal regulation of cohabitation, this book will undoubtedly have both considerable impact and also a wide readership. However, it is arguable that the value of this book is not limited solely to those interested in a historical perspective on the legal treatment of non-formalised relationships. Drawing upon a wide array of sources, Probert's meticulous and incisive analysis of this area tells us far more. It provides insight into the evolving notion of “family” and the significance of relationship status. It stimulates debate as to the relationship between law and social change which naturally touches upon how social trends influence law-makers and the courts. More importantly, the central thesis of the book tells us of the importance of interrogating assumptions about law and social practice. It is only once this is done that a better foundation can be generated for the purposes of debating how the law should develop in the future. These broader issues are of appeal not only to family lawyers but also to all that are interested in how law incrementally develops in response to dynamic social change.