The abolition of Latin American slavery has long been recognized as a complex and contentious process stretching over several decades. Historians who study that process face the challenge of incorporating into their stories multiple actors: state officials, lawyers, journalists, activists, and, not least, enslaved people actively seeking freedom. That approach has generated a rich historiography, ranging from early work by Emília Viotti da Costa, Robert Conrad, Rebecca Scott, and others up through recent books by scholars such as Jeffrey Needell, Angela Alonso, and Yesenia Barragan. Based on deep and meticulous research and clearly and effectively written, Magdalena Candioti's Una historia de la emancipación negra is a worthy addition to that literature.Candioti begins her story with the profoundly destabilizing impacts of national independence on the institution of slavery. Revolutionary rhetoric that compared Spanish rule to enslavement and that promised to strike off the chains of colonial rule inevitably raised the question of whether that promise included the chains of slavery. Since many, and probably most, independence leaders were themselves slave owners, this question struck uncomfortably close to home. The contradiction between national freedom and continuing enslavement produced first the abolition of the African slave trade in 1812 and then the Free Womb Law (Ley de Libertad de Vientres) the following year. The law decreed that children of enslaved mothers would continue to serve their mothers' enslavers until reaching the age of majority (16 for females, 20 for males), at which point they would achieve full freedom.One ambiguity of the new law was whether children of enslaved mothers were born free (and were therefore ingenuos) or whether they were born enslaved and then immediately freed (and were therefore libertos). The Reglamento de Libertos, approved a month after the initial law, settled that question and laid out the regulations governing this new class of persons. In 1840, a court in Tucumán found that “los derechos y obligaciones que tiene el patrono [enslaver of the child's mother] respecto del liberto son los mismos que tiene un amo respecto de un esclavo; . . . ambos tienen el derecho de servirse y sacar del liberto y esclavo una justa utilidad” (p. 88; emphasis in original). Patronos were also free to sell their libertos (after the age of two) to other owners, and Candioti finds many instances of slave parents going to the police to request assistance in getting their children back, “con suerte dispar” (p. 86).Meanwhile, those Africans and Afro-Argentines who had been enslaved at the time of the Free Womb Law's passage remained enslaved. They continued to pursue freedom in the same ways that they had pursued it under colonial rule, through negotiating with their enslavers and accumulating the savings with which to buy their freedom. Candioti finds that the same system of coartación (enslaver and enslaved person agreeing in advance on a fixed purchase price) that existed in Cuba, Peru, and other countries operated in Argentina as well, and that, as in other countries, women were clearly favored over men in grants of manumission (pp. 111–12).Independence further undermined slavery by opening another route to freedom, through military service. Several thousand slaves were conscripted into rebel armies and then into provincial forces during the civil wars that followed independence. Slaves could also volunteer for service, and many did so. Conscription was no guarantee of freedom, however, since many draftees died or returned from service broken in health.With no new slaves being born or imported from Africa, by the 1840s slavery's days in Argentina were clearly numbered. Reviewing the debates in the constitutional assembly of 1852–53, Candioti finds that Article 15, which abolished slavery, was approved with zero discussion, no voices speaking either for or against the measure. The constitution made no provision for compensation to former enslavers, but several provinces did institute programs that compensated owners for their liberated property.Throughout her book, Candioti stresses the tensions and disconnects between legal principles and daily lived reality, and the constant process of negotiation among enslaved persons, libertos, enslavers, and state officials. She has dug deep into administrative, judicial, and church archives and into nineteenth-century newspapers, and has made excellent use of the outpouring of research in recent years on Black and subaltern history in Argentina. Finally, rather than confining herself to Buenos Aires, she surveys conditions and practices throughout Argentina while simultaneously calling for further research on those provinces. All these aspects make the book a signal achievement and the obligatory reference for how slavery came to an end in Argentina.