The aim of the author is to provide a comprehensive account of the scientific career of Carl Peter Thunberg (1743–1828), which encompasses his voyage to Tokugawa Japan, examines his network of European correspondents and patrons, and documents his experiences as a surgeon travelling with Dutch East India Company (VOC). These different facets of Thunberg's career have previously been scattered across different countries and disciplines, and the author brings together all the strands in one volume. The study is ordered chronologically, and begins with an offer by the Dutch botanist Nicolaas Laurens Burman to Thunberg in 1771, to undertake a plant-collecting journey to Japan. The following chapters chronicle his travels to South Africa, Java, Japan and Ceylon, and his return journey to Europe in 1779, and conclude with an analysis of his scientific publications and academic career at the University of Uppsala.

Thunberg was one of Linnaeus's students, and the only European scientist to visit, and publish his observations of, Tokugawa Japan in the eighteenth century. His travel account, and his collection of rare Japanese plant specimens, would be of particular interest to naturalists, because, with the exception of the VOC, Japan was closed to Europeans. Thunberg's decision to embark on an expedition halfway across the world was not without risks; it was not at all certain that he would reach his destination and a number of Linnaeus's students had died while plant collecting in foreign lands. For any ambitious young naturalist, career planning was an important factor in undertaking such an arduous journey. It was a means of securing patronage and corresponding with other European naturalists. Thunberg's voyage to Japan was sponsored by Dutch financiers in Amsterdam, but would not have been possible without his salary as a surgeon with the VOC.

As Japanese flora was relatively unknown, plant collectors were eager to receive species uncommon in Europe. They believed that the plants would thrive, as the climate of Japan was similar to that of the Netherlands. Thunberg was working for a number of patrons, which was not unusual for a European botanist. His Dutch patrons (including the Botanical Garden in Amsterdam, the Hortus Medicus, and members of Amsterdam's ruling oligarchy) would pay for his daily expenses, including the cost of sending the specimens, and in return they would receive the rare and new plants. His Swedish patrons (including the Royal Academy of Sciences in Stockholm) provided occasional financial assistance, especially in the final years of his voyage, and support in career building. Thunberg's private collection of plants would lay the foundation of his academic career and provide the basis for his scientific publications, after his return to Sweden. It was inevitable that, with conflicting interests, tensions arose among his patrons, and Thunberg's financial situation was often precarious with only sporadic payments from his Dutch patrons.

Thunberg's fifteen months in Japan were spent mostly confined to the Dutch trading post on the tiny artificial island of Deshina. This chapter is the highlight of the book. Confinement restricted his movements and his opportunities of communicating with the Japanese; however, Thunberg was able to set up a system of exchange with the Japanese intellectuals he encountered. In return for his expertise in Western medicine and botany (he provided a method of treating syphilis), he received exotic specimens, artefacts and information on Japanese culture.

There were many difficulties involved in obtaining specimens from a closed and inaccessible country but Thunberg was able to collect six hundred species of plant in various forms: dried specimens, seeds, live trees and shrubs. His first priority was sending specimens to his patrons, especially to those who commissioned his travels. These unique plants could be used for medical purposes (to combat disease) and were extremely valuable as objects of prestige. Unfortunately, not all shipments reached their destination, and when one arrived in Europe it had been opened on the way and was half empty.

In only five years after returning to Sweden, Thunberg secured Linnaeus's old chair as professor of medicine and botany at the University of Uppsala. His rapid rise at Uppsala between 1779 and 1787 was the result of both royal favor and his unique collection of Japanese specimens and artefacts. This collection formed the basis of his scientific work and was shown to important visitors, or gifted to colleagues and patrons. Thunberg presented his collection of coins to Gustav III, who included it in the Royal Coin Cabinet, and donated his own natural-history collection to the University of Uppsala.

Gustav's donation of a building for this collection (the future Linneanum), and a new University Garden, were seen as a response to Thunberg's gift. This book illustrates the importance of gift exchange throughout Thunberg's career, and reveals the difficulties faced by naturalists when their patrons lost influence or died. His position of demonstrator at Uppsala was secured by his Swedish patrons in return for gifts of plant specimens. However, after Gustav's death in 1792, Thunberg was unable to secure the patronage of his successors, and his preferment came to an end. This book, and the many fascinating facets of Carl Peter Thunberg's scientific career, will interest historians of Japan, as well as botanists and historians of science.