The book edited by Jean Allain is a collection of essays written by seventeen renowned scholars with the aim of analysing the evolution in the legal understanding of slavery, using the definition enshrined in Article 1(1) of the 1926 Slavery Convention – which described it as ‘the status or condition of a person over whom any or all the powers attaching to the right of ownership are exercised’Footnote ¹ – ‘as its pivot’ (p. v). The book is subdivided into four sections, analysing respectively slavery from an historical point of view (sections 1 and 2), the 1926 definition of slavery (section 3), and contemporary slavery (section 4). According to the authors, the book clarifies the contours of the legal concept of slavery, as defined in 1926, guides the reader in understanding whether forced labour, debt bondage, child soldiering, and forced marriage are forms of slavery (p. 1), and ʻdetails a manner of approaching the definition that provides for the type of legal certainty required in a court of lawʼ (p. v). However, for various reasons the book is not successful in shining a bright light on this issue.

In this respect, the first two sections of the book, as well as the fourth – with the exception of Chapter 16 – are not fully in line with the book's aim. This is not to say that the chapters included in these sections are not interesting per se. Section 1 – which opens with Honoré's account of slavery in ancient Roman law, followed by Helmholz's review of the definition of slavery between the twelfth and the early seventeenth centuries, Freamon's examination of slavery in Islamic law, Cairns’ piece on the law of slavery in the eighteenth century and, finally, Drescher's historical analysis of the international law on slavery starting from Roman law – is well organized and written, but it offers little help in clarifying the interpretation of the 1926 definition. The same can be said for the chapters included in the second section – written respectively by Finkelman, Mileo Gorsuch, Scott, Engerman, and Carter – that are equally interesting, notwithstanding the fact that, in this case, the choice of focusing only on the American experience can also be criticized.

Another important issue is the fact that, at times, some of the authors use different definitions of slavery, or express disagreement towards the interpretation of the concept of slavery, or of terms that are relevant for its understanding, as provided in other chapters. An example is the fact that some of the sociologists and historians continue to refer to the sociological definitions of slavery that they use in their work in this field, in some cases specifying them better than they did in their previous work. For instance, Honoré defines a slave as a ʻperson who, in fact, though not in law, is subordinate to an unlimited extent to another person or groups of persons . . . and who lacks access to state or other institutions that can remedy his or her inferior statusʼ (p. 16), Patterson sees slavery as the ʻviolent, corporeal possession of socially isolated and parasitically degraded personsʼ (p. 329), and Bales as:

In this respect, it is also interesting to note that, in his important book Slavery as Social Death: A Comparative Study, Patterson considered that the attempt aimed at defining slavery in terms of property rights – namely, the premise on which the 1926 slavery definition is founded – was a mistake.Footnote ² Therefore, the reason(s) that led him to contribute to an edited collection of essays, having instead the aim of clarifying such legal definition, should have been explained to the reader, as this move constitutes a major departure from his previous work in the field. Moreover, in Chapter 17 Patterson argues that there are today only three different kinds of slavery: chattel slavery – the one that is still present in countries such as Mauritania and Niger; the worst forms of child labour (WFCL); and trafficking and the exploitation of women for domestic and commercial sexual purposes (p. 343). In addition to this, he argues that the practice of debt bondage/bonded labour does not amount to slavery. It remains unclear how Patterson selected some practices – namely, chattel slavery, the WFCL, and trafficking of women for domestic and sexual exploitation – and excluded others – debt bondage – from the realm of interpretation of the 1926 definition of slavery. The analysis is thus conducted in sociological terms and it is not based on sound legal premises. Furthermore, it is not clear why the author excluded trafficking of men and young boys and how he would define the practices that he included or excluded from the interpretation of the 1926 definition of slavery.

Moreover, Patterson proposes an estimate on the number of slaves in the world – namely 8,978,900 (p. 350) – that is lower in respect of the one of 27 million offered, since the end of the 1990s, by Bales, who instead includes bonded labourers.Footnote ³ Disagreement is also to be found between Quirk and Bales, as the former claims that the definition adopted by the latter ʻlacks a clear legal foundation, and it is therefore open to charges that this is simply one person's opinion as to what slavery might look likeʼ and focuses too much on economic exploitation (p. 254).

All these different points of view are very interesting; however, in a purely international legal discourse they do not offer clear-cut guidance on how the 1926 definition of slavery ought to be interpreted according to the rules of international law, or in suggesting a possible interpretation to be offered to national judges and prosecutors.

As regards section 3, the part that is more relevant from the point of view of international law, a few repetitions and deficiencies can be found. In respect of the former, the chapters by Allain, Hickey, and Quirk partially overlap when they look at the drafting history of the 1926 slavery definition. However, while Quirk is in agreement with Allain that practices to be classified as slavery have to ʻsatisfy the operative threshold of “powers attaching to the right of ownership”’ (p. 259), partial disagreement among the two authors is found in the number of practices that meet this criterion. Allain believes in fact that there is only one type of slavery, including all the practices that meet this threshold, while for Quirk there are multiple ones (p. 258).

Moreover, the identification of the institutions and practices affecting children included in Article 1(d) of the 1956 Supplementary Convention on the Abolition of SlaveryFootnote ⁴ with child trafficking made by Allain (p. 207), Quirk (p. 261), and Drescher (p. 99) is wrong. As already stated elsewhere, this attempt looks like an ahistorical “marketing operation” of the term ‘trafficking’ that lacks any legal standing.Footnote ⁵ From the point of view of international law, in fact, the term ‘child trafficking’ was used – and defined – for the first time by the 2000 Protocol to Prevent, Suppress and Punish Trafficking in Persons, in Particular Women and Children; before that, since the beginning of the 20th century the term ‘traffic’ had been instead used as a way to identify the phenomenon of the ‘white slave traffic’ – as opposed to the Transatlantic slave trade – and had been included in the international treaties adopted in less than 50 years to fight against it.Footnote ⁶ In this framework, the term identified the recruitment, through, inter alia, abduction or deception, of young women, their transfer abroad, and their exploitation in brothels. Moreover, the term ‘child traffic’ is also used in Article 35 of the 1989 Convention on the Rights of the Child,Footnote ⁷ even if no definition is provided in this framework. However, during the drafting process that led to the adoption of the final text of this provision, delegates emphasized that the concept is broad in scope and includes cases leading to child sexual and labour exploitation and commercial adoptions.Footnote ⁸ Equally incorrect is the contributors’ reference to servile marriage when identifying the multiple practices included in Article 1(c) of the same treaty.Footnote ⁹

Unfortunately, the analysis of the history of the international attempts aimed at fighting against slavery conducted by Allain and Quirk stops with the account (and harsh criticism) of the work of the UN Working Group on Contemporary Forms of Slavery, without taking into any serious consideration the more recent work of the UN Special Rapporteur on Contemporary Forms of Slavery (and/or that of the Special Rapporteur on Trafficking in Persons, Especially Women and Children). Moreover, while Allain and Quirk criticize the use of the term ‘slavery-like practices’ by the UN Working Group on Contemporary Forms of Slavery (p. 210–211 and 263), on the grounds that it permitted it to also discuss practices that, from a legal point of view, would not fall into the definitions included in the Conventions against Slavery, they do not abide to a higher standard from the point of view of international law when they, respectively, laconically refer to ‘human exploitation’ (p. 199) and ‘human bondage’ (p. 262), without providing the reader with specific legal definitions of these terms.

The other two chapters included in section 3, written by Hickey and Penner, focus on property rights in civil law. However, Hickey and Penner disagree on the concept of the powers related to the right of ownership included in the 1926 slavery definition (p. 240). Moreover, while these two authors promote a civil law interpretation of the term ownership, making reference to property rights, the book lacks a much-needed focus on criminal law in discussing a phenomenon, that is, first of all, an odious crime. In this respect, Penner is the only one who recognizes that ʻvagueness and uncertainty in the definition of an offence are not acceptable in the criminal lawʼ and that the criterion of confronting practices with the threshold of the ʻexercise of the powers attaching to the right of ownershipʼ alone is not sufficient (p. 249).

An interesting perspective on the judicial interpretation of the 1926 definition of slavery by some international and national courts is offered by Cullen in Chapter 16 included in section 4. However, the author adopts a very simplistic perspective when she claims that ʻthe essence of forced labour [is] coercion, whereas the essence of slavery is the powers attaching to ownershipʼ (p. 320–1). Forced labour is defined by Article 2(1) of the ILO Convention N. 29 as ʻall work or service which is exacted from any person under the menace of a penalty and for which the said person has not offered himself voluntarilyʼ.Footnote ¹⁰ In this respect, it is interesting to emphasize that the ILO interprets the terms ‘menace of a penalty’ in a broader way than Cullen does, thus including ʻcriminal sanctions as well as various forms of coercion such as threats, violence, the retention of identity documents, confinement, or non-payment of wages. The penalty may also take the form of a loss of rights or privilegesʼ.Footnote ¹¹

A final remark should be made on the Bellagio-Harvard Guidelines on the Legal Parameters of Slavery annexed to the book, that were unanimously adopted by all its contributors (pp. 376–80). As stated in the preface: ʻThe Guidelines provide a reading of the definition which is internally consistent with its property paradigm while capturing the essence of contemporary slaveryʼ (p. v). Some interesting points aimed at reducing the vagueness of the 1926 slavery definition were made, such as: the reference to control, a final aim of exploitation for the offence, and the deprivation of liberty in Guideline 2; and the indeterminate duration of the practice in the eyes of person subjected to it in Guideline 3. However, doubts remain about some of them. For instance, with a reference to the fact that the offence of subjection to slavery shall have an aim of exploitation, two remarks can be made here: first of all, the term ‘exploitation’ is left undefined and, second, this reading of the 1926 slavery definition adds an element that is not included in the original text. While it is true that such addition is made in some penal codes as a way to guarantee determination and stringency to the offence of slavery,Footnote ¹² it might well be that other countries did not include it in their penal laws.Footnote ¹³ In addition to this, the term ‘control’ is interpreted in Guideline 3 as implying physical control or ʻother more abstract manifestationsʼ of it, including ʻattempts to forge a new identity through compelling a new religion, language, place of residence, or forcing marriageʼ on the victim (p. 376); however, no reference is made to psychological forms of control and the authors do not clarify if these should be taken into consideration or not.

It seems, therefore, that while the Guidelines might provide help, national judges will still have to struggle with the international legal definition of slavery and with those of other offences such as, inter alia, servitude, forced labour, the worst forms of child labour and trafficking in persons, and first of all, understand how (and if) their state has included some or all of these offences in their penal law(s), how they have defined them, and, eventually, how these offences relate to each other in their own national system.

Apart from these criticisms, the book includes a great richness and variety of perspectives on slavery offered by some of the leading experts in this field; an attempt could have been made to guarantee more consistency between the original aim and the final result and to avoid repetition. It is evident, however, that this collection will be of interest to all those who are already quite well versed in this field and it will surely continue to generate debate on the legal understanding of the definition of slavery under international law.