[Cross-posted from New Books in Science, Technology, and Society] Abena Dove Osseo-Asare’s wonderful new book is a thoughtful, provocative, and balanced account of the intersecting histories and practices of drug research in modern Ghana, South Africa, and Madagascar. Bitter Roots: The Search for Healing Plants in Africa (University of Chicago Press, 2014) tells the stories of six plants, all sourced in African countries, that competing groups of plant specialists have tried to transform into pharmaceuticals since the 1880s. The leaves and roots and seeds of the book’s narrative collectively map the contours of a story that emerges from a crucial and germinal tension: on the one hand, much of the history of the plant sciences in these African spaces is motivated by a race for patents and scientific credit; at the same time, the mobility of plants across the borders of Osseo-Asare’s study has complicated efforts to assign priority of discovery to individuals or groups, and in fact challenges the very notion of a “traditional†or “indigenous†body of knowledge in the first place. Simultaneously a carefully situated ethnography and a history informed by a material archive that encompasses pages and petals, the book explores that tension in a critical assessment of what it means to talk about “African†science or “local†knowledge. Bitter Roots will deservedly have a wide audience in African studies, science studies, and the histories of medicine, pharmacy, and botany.