Missionary Scientists explores the scientific activities of Jesuit missionaries in colonial Spanish America, revealing a little-known aspect of religions role in the scholarship of the early Spanish Empire. Grounded in an examination of the writings and individuals authors who were active in South American naturalist studies, this study outlines new paths of research often neglected by current scholarship. What becomes clear throughout Missionary Scientists is that early missionaries were adept in adapting to local practices, in order to both understand the scientific foundations of these techniques and ingratiate themselves to the native communities. Spanning the disciplines of history, religion, and Latin American studies, Missionary Scientists reshapes our understanding of the importance of the Jesuit missions in establishing early scientific traditions in the New World.