This book brings together the two, though rarely conjoined, subfields of slave and free labour history to explore the evolution of working-class identities in Brazil's then capital city. Rio de Janeiro in 1850, home to Brazil's largest urban slave population, provides Badaró Mattos with an ideal case study to explore slavery's influence on the formation of urban labour markets and the class identities that sprang from and in turn shaped these markets. Slaves often worked alongside free and freed workers in Rio's burgeoning manufactories and industrial establishments, and they too participated in work stoppages and other actions to pressure owners and authorities to improve conditions, wages, hours and other injustices. Badaró Mattos analyses one of the earliest known work stoppages in 1854 when some 30 slaves refused to continue work on the Ponta d'Areia foundry and shipyard belonging to the industrialist Baron, later Viscount, of Mauá, in Niterói (across the bay from Rio) unless authorities released their incarcerated workmates. Ponta d'Areia employed some 600 workers, one quarter of whom were slaves, the largest private industrial establishment in the region. These and many other incidents demonstrate that slaves played vital roles in the development of worker actions which, Badaró Mattos argues, referencing E. P. Thompson, served as the crucible of an emerging class consciousness (pp. 8–9).

The author organises his study thematically into four chapters: work, urban life, and the experience of exploitation; forms of organisation; resistance and struggle; and consciousness. Though each chapter proceeds on roughly chronological lines, some repetitive overlap between chapters is almost inevitable in this style of text smithing. The monograph offers a concise synthesis of the evolution of different urban labour actions and organisations based largely on the labour press and recent secondary studies of Rio's labour movements. In this way, Laborers and Enslaved Workers brings the evolving literature on slave, free and freed labourers into dialogue.

The author surveys the evolution of worker organisations. Slave and free workers relied on different organisations to defend their interests. These evolving entities influenced one another as they emerged and many workers actively participated in more than one of these entities over their lifetimes: mutual aid associations, Catholic lay brotherhoods, emancipation organisations, festive organisations (cordões and ranchos carnavalescos – Carnival associations – and escolas de samba), maltas de capoeira (neighbourhood-based groups that practised this Afro-Brazilian martial art, dance and musical form) as well as more formal trade unions and working-class political parties. The law barred slaves from membership in government-organised mutual aid societies, but they could participate in Church-sanctioned lay brotherhoods and informal cultural and political organisations like Carnival groups and capoeira maltas. In essence, lay brotherhoods gave slaves a means to organise, often in terms of their ethnicity, to provide their members with treatment and medicine for illnesses, pensions, funeral costs and, in some cases, the purchase of their freedom. The Conservative Party frequently employed capoeira maltas that included enslaved members as informal security forces during elections that shaped formal politics in the 1870s and 1880s, even though bondsmen could not vote. Many free workers of all colours and nations joined lay brotherhoods that formed around the trades they practised, but these organisations typically barred slaves. The struggle for abolition brought many Carioca workers together in a common struggle for freedom, but even after slavery's 1888 abolition, divisions among workers and their organisations did not disappear. Lines of cleavage between former slaves and free workers along with differences of colour, nationality, gender, education, ideology and class continued to divide workers into the early twentieth century. Even so, these workers often managed to find ways to collaborate collectively to define and defend their interests in planned strikes and spontaneous uprisings (e.g. the 1880 Vintem Riot and the 1904 Vaccine Revolt). In work, political actions and leisure Carioca labourers found their own means to fashion their unique working-class consciousness from both international influences and local experiences and traditions that fed the development of more formal labour unions and working-class political parties.

In some ways, Badaró Mattos's synthesis raises more questions than this text can possibly answer, but this speaks more to the nascent character of exploring workers acting and organising across the lines of slavery and freedom (p. 162). The author adroitly uses these lacunae to point the way to fruitful future research which may include other categories subject to coercive labour extraction such as free Africans, sailors, soldiers, military apprentices, convicts and orphans. This synthesis will help scholars to deepen inquiries into how Rio de Janeiro's history of slavery and colonial Portuguese conceptions of the ‘mechanical defect’ (the stigma attached to manual trades) complicated workers’ efforts to promote the dignity of physical labour and organise themselves in ways that were quite distinct from workers in northern Europe. There are a few infelicitous translations: ‘diaries’ instead of ‘dailies’ in reference to daily newspapers, Carnival ranchos as ‘ranches’, but these are minor quibbles for a work that should have broad appeal to those interested in labour and the multifaceted subfields that it invokes.