The Spanish Empire's attempts to exert control over the cinchona tree and its bark, and their eventual failure, are the focus of this fascinating study, which illuminates further the entanglements of European sciences and empires. Based on meticulous archival research, it places the story of quina (a medicinal tree bark harvested from various species of cinchona trees in South America) at the centre of the historiography surrounding the Atlantic world. By highlighting the wider economic, political and social forces at play, Matthew J. Crawford provides a different perspective from traditional linear histories of the bark's properties and usage. The first part of his study, focusing on the mid-seventeenth to mid-eighteenth centuries, traces the development of quina from a local medicament of the Andean world to a global botanical commodity. Indigenous, Atlantic and imperial networks all played key roles in this transformation, which saw a significant increase in the volume of quina imported from South America into Europe in the early eighteenth century, primarily through Cádiz.

By the mid-eighteenth century, the quina trade was booming and the Spanish Crown decided to intervene directly. In 1751, it established a royal reserve of cinchona trees in Loja in the viceroyalty of New Granada (now southern Ecuador) to supply the Royal Pharmacy in Madrid with the best-quality quina available. This was an attempt to assert control over the production and distribution of the medicament and also to introduce techniques and standards for classifying the bark throughout the empire. Differing interpretations of the bark's quality and taxonomy existed and the Spanish Crown wanted its officials and institutions to be arbiters of knowledge in these disputes.

The second half of the book focuses on the conflicts that arose from these imperial attempts to assert control. Crawford's flair for recounting contentious episodes engages the reader with the politics of the Spanish Atlantic world and vividly illustrates the challenges faced by Spanish pharmacists and botanists in their dealings with bark collectors, merchants and local officials. Rather than the simple dynamic of a European centre and a colonial periphery, Crawford considers the interplay between two centres of knowledge production on different sides of the Atlantic. The relationship between the Royal Pharmacy in Madrid and the royal reserve in Loja reflected the different epistemic systems in play. In 1773 the royal pharmacists judged that a shipment of quina from Loja to Madrid, weighing over 15,000 pounds, was unsuitable for royal purposes such as giving as gifts to dignitaries, treating royalty or distributing to royal and military hospitals. Consequently, the royal pharmacists sent instructions to Loja on the collection, drying, packaging and transport of quina, accompanied by a sample of what they judged to be the highest-quality bark that the reserve could send. However, when the bark collectors demonstrated that the sample sent by the Royal Pharmacy was not from Loja, but from the nearby province of Jaen, the primacy of local knowledge was asserted.

Nevertheless, the Spanish Crown still sought to enforce the authority of European science and utilized other sources of expertise, particularly botanical. In 1790 Vicente Olmedo was appointed co-director of the royal reserve in Loja with the official title ‘botanist–chemist’. His appointment marked a significant shift in how scientific skills were deployed in the Spanish Empire. In the previous decades, pharmacists and botanists had served in an advisory capacity, but in 1790 Olmedo was sent as an agent of empire to South America with responsibility for the physical production of a botanical commodity. The increasing scarcity of cinchona trees and continued fraud in mixing quina with other tree barks were issues of particular concern. However, problems of terrain, labour, poverty and a lack of technology thwarted attempts to introduce cinchona plantations, instruct indigenous labourers and produce quina extract in Loja. In addition to these practical problems, opposing visions of regalist and mercantile control of the political and economic order of the Spanish Empire divided experts both in Spain and in South America, with these intellectual splits central to a major dispute among naturalists over the botanical classification of quina.

Through an in-depth analysis of the debates surrounding the categorization and properties of quina, Crawford's book demonstrates the strengths but ultimate fragility of European science in the contexts of colonial governance and society. A compelling narrative of events draws the reader into the scientific, political and commercial milieu of the Spanish Atlantic in order to study the dynamics of knowledge production. This book is an impressive contribution to existing scholarship on early modern science and medicine. It enhances our understanding of the acquisition and circulation of knowledge and is a valuable component of the ongoing discussion regarding the effectiveness of European science as a tool of empire.