The history of science in the early modern Iberian world is a blooming field. The recent decades have provided excellent contributions in English from historians based in both US and European universities and research centers, not to mention myriad studies authored by scholars based in the Iberian Peninsula, who usually publish in their own languages. As in many other areas of history, the Portuguese side of this story is often the poor cousin. This is especially true for the subject of colonial medicine prior to the nineteenth century, which is what Assembling the Tropics primarily covers; hence a reason, among many others, to welcome Hugh Cagle's first book. We have substantive studies for Dutch and British colonial medicine, but the Portuguese empire has lacked so far an all-encompassing, argumentative study, despite the solid work produced by several historians, especially Timothy Walker.Written at the crossroads of various fields, Assembling the Tropics makes an artful use of the available primary sources and displays mastery of the relevant literature for different cultural zones of the early modern world. The book covers more than two centuries, from the mid-1550s to the late 1770s, and takes the reader successively from sub-Saharan Africa (chapter 2) to the Indian Ocean world (chapters 3 to 5) and the South Atlantic (chapters 6 to 8). Cagle's purpose and research agenda are clearly presented in the first chapter of the book and recalled in its epilogue: the author seeks to investigate “distinctive cultures of inquiry” in the Portuguese empire concerning nature and disease in order to understand developments on the ground, “in each theater of colonial engagement,” and therefore “to reorient and pluralize the history of early modern science” (p. 309).In so doing, Cagle rightly refuses a teleological (often-nationalistic) view of early modern Portuguese science, which is invariably associated with the rise of modernity and the historiographically controversial scientific revolution. He likewise questions the centrality of Lisbon and the metropole while giving room to medicinal developments on the ground, be it in South Asia or the South Atlantic. Needless to note, this exercise of relocation is incompatible with the diffusionist paradigm or the center-periphery model. Alternatively, such relocation implies strong engagement with a historiographical current, very much in vogue, that underlines the importance of movement and circulation, porosity and fluidity, and entanglements and connections. Finally, Cagle embraces a holistic view of the Portuguese empire; instead of spatially segmenting his work, he pays equal attention to the Indian Ocean and Atlantic Ocean settings as well as to the intriguing intertropical phenomena at stake.Assembling the Tropics brings into play a plethora of figures, texts, places, and practices. Jesuit missionaries and obscure native practitioners—the embodiment of relocated expertise—populate this work. It is clear, though, that the Asian section of the book is dominated by Garcia de Orta and his Colóquios dos simples, e drogas e cousas medicinais da India (published in Goa in 1563), while the book's Atlantic section is molded by Aleixo de Abreu's Tratado de las siete enfermedades (published in Lisbon in 1623) and Ambrósio Fernandes Brandão's Diálogos das grandezas do Brasil (written in 1618). These are chapters of impeccable scholarship, but it might be problematic to rely on a handful of authors and materials in order to demonstrate—without, somewhat ironically, being able to avoid a certain teleological stance—how the tropics were fully assembled by the late seventeenth century; this leaves the impression that Cagle's arguments and evidence are sometimes stretched too far.On the other hand, if the emphasis is put on “proliferating centers and cosmopolitan colonies,” then we need to take the argument a step further (p. 16). What about scholarly medicinal conversations across the Iberian empires, with cities like Mexico City, Lima, and Manila probably taking an active role? (Abreu's Tratado was written in Castilian, and one wonders what its readership was in colonial Spanish America.) Were there numerous, even if tense, scientific interactions with the Dutch in both oceans? (Cagle hardly mentions Willem Piso and Jacobus Bontius.) And why should East Asia be excluded from the Indian Ocean world when we know that Macao and Nagasaki were the locus of significant hybrid medical experiments in this period? The author favors the study of human entanglements but indirectly contributes to compartmentalizing the subject matter.Despite these shortcomings, Assembling the Tropics constitutes an excellent and much-needed scholarly endeavor written in a clear and engaging style. Cagle's work is geared toward historians and students of the Portuguese empire and the history of science (namely medicine) in early modern times but certainly has the potential to attract a much wider audience.