By putting in the same phrase two phenomena usually considered to be chronologically and conceptually distinct, the title of Benedetta Rossi's From Slavery to Aid expresses the signal contribution of this compelling work. The product of some twenty years of research in Ader – roughly the southern half of the contemporary Nigerien administrative region of Tahoua – Rossi's book makes multiple, linked arguments that are not quite accurately captured in its subtitle, Politics, labour, and ecology in the Nigerien Sahel. Nor can they be readily encapsulated in a single review. That said, the book's central question is why, in this area of the Sahara-Sahel, slavery has proven so resilient and a transformation in labour so elusive in the context of scarcity and ecological adversity.

The question, and indeed the circumstance, is particular to the region, which is in turn largely defined by its ecology. Ader straddles the sharp edge of the Sahel. Rain-fed agriculture is feasible, but hardly profitable. Herders practise transhumance. Apart from long-distance trade, which absorbs relatively little labour, there is no productive activity that would support a sustainable wage. In the twentieth century, migration became the clear alternative to penury, particularly given the relatively high wages available in Nigeria, but nearly all migrants were male. In short, labourers are available – in a region in which the population has grown rapidly without ever becoming dense – yet labour is unobtainable or unprofitable. How to square this circle? Coercion.

Such coercion, it turns out, has a complex history in Ader. Before the French conquest, local forms of governmentality – a Foucaultian concept to which Rossi is indebted but not wedded – relied on the control of movement rather than of territory. Rossi contrasts this practice of governing mobility, which she terms ‘kinetocracy’, with French ideas of government that were territorially bound, linking populations to specific locales. Through World War I, the former model prevailed. Tuareg ‘chiefs’ of the Iwellemmeden Kel Denneg and Kel Gress, who mastered both mobility and the means of violence, demanded ready access to the scarce resources of sedentary Hausa and Asna communities. They extracted from the peasantry more or less at will, but had little else at stake in the ability of those communities to reproduce themselves. After a brutal (and late) military conquest of the region, French colonizers followed much the same pattern. In a difficult environment very weakly penetrated by capital, they procured labour and extracted resources by force, irrespective of the supposed end of slavery. In short, facing similar ecological constraints but drawing on two distinct governing ideologies, Tuareg chiefs and French officers pursued much the same solution.

That began to change in 1946, when such long-standing practices were thrown into question by the abolition of the colonial administrative ‘code’ known as the indigénat, which Rossi presents (reductively in my view) as primarily a tool for procuring labour. A new form of ‘developmentalist government’ slowly emerged. In the decades to come, the anticipated transition from slavery to some form of waged labour never took place. Rather, in keeping with President Seyni Kountché’s vision of Niger as a ‘development society’, the aid industry became rooted in Ader. Locally, it took the form of an Italian development initiative known as the Keita project, to which Rossi devotes an illuminating chapter. While aid never enabled the poor to escape poverty, Rossi argues that food-for-work programmes in particular enabled poor women to survive periods of scarcity and, for some, to pay the symbolic price of enfranchisement (‘ransom’) to the descendants of their ancestors’ masters. The particular practices of the aid industry in Ader, therefore, partly displaced the vestiges of slavery as a mode of dependency in a way that colonial capitalism (such as it was) never had. This did not fundamentally alter social hierarchies – whether between classes or within households – but it did open up another possibility for creating and maintaining reciprocal (if distant and uneven) relationships.

Rossi approaches this dense yet dynamic weave of relationships through what she terms a ‘perspectival’ mode of exposition that privileges the viewpoints of diverse actors, ranging from bori adepts to labour migrants, colonial administrators, and development agents. This approach offers a holistic view on social and political change, but it also threatens at points to dull the thrust of the argument. Indeed, the innovation in Rossi's work lies in the framing of the question itself. The greatest of its many strengths – did I mention that she uses at least five languages? – lies in the depth of Rossi's research, and particularly in her ethnographically rich analysis of women's work. Any future history of labour, slavery and aid in the Sahel – or indeed in other ecologically marginal settings – would do well to engage with this landmark book.