Outside Denmark, Hans Christian Ørsted (1777–1851) is primarily known for his discovery of electromagnetism in 1820. Within his native land, Ørsted is also remembered for his active involvement in the cultural and political life of the nation, and as a driving force behind the establishment of a Polytechnic Institute and the Faculty of Science at Copenhagen University. Today, the building that houses the Departments of Mathematics, Chemistry and part of Physics at Copenhagen University carries his name. With Reading Nature's Mind, Dan Christensen has written an impressive biography of an important thinker. First published in Danish in 2009, it is a most welcome addition to the growing body of Danish history-of-science literature published in English, and it is a significant contribution to the research field.

Reading Nature's Mind is organized both chronologically and thematically into seven sections and sixty-three chapters. Christensen's primary theoretical framework is his claim that Ørsted was deeply influenced by Kant's metaphysical philosophy and, contrary to what has previously been argued, had little to do with Schelling and German Naturphilosophie. Part 1, entitled ‘The student’, is centred on the early life and education of Ørsted and his brother Anders. Part 2, entitled ‘The cosmopolitan’, traces Ørsted's first tour around Europe. By examining the early intellectual life of the two Ørsted brothers, Christensen convincingly shows that Kant's dualistic philosophy, with its distinctions between nature and mind, between the phenomenal and noumenal realms, left its lasting mark on Ørsted's lifelong project to establish a research programme for a ‘dynamical physics’ with ‘matter’ as a product of polar forces. Ørsted became familiar with Johann Wilhelm Ritter's work on electromagnetism in relation to the ‘galvanic’ controversy around 1800, and the two formed a lasting friendship during Ørsted's first visit to Germany. The significance of their bond is key to the development of Ørsted's research programme. In 1802–1803 Ørsted and Ritter attempted to win the Napoleon Prize with Ritter's galvanic experiments and their rejection of the corpuscular theory, but ultimately failed. However, Ørsted and Ritter remained convinced that the dynamical theory had defeated the corpuscular system.

Christensen gives a fine overview of the structural organization of universities in Denmark, Germany and France, and how this affected the contemporary research culture. For example, Christensen shows how Ritter and Ørsted were both dependent upon the assistance of wealthy patrons to facilitate their research. It was Ørsted's goal to acquire a paid position and to establish a school for science at Copenhagen University. Christensen examines these struggles and subsequent successes in detail in Part 3, entitled ‘The researcher and teacher’; Part 6, ‘The organiser’; and Part 7, ‘Fame and tribulations’. Part 4, ‘The spouse’, gives an interesting insight into the Ørsted brothers’ role in the Danish pantheism controversy and their heated discussion with the Danish pastor, author and politician N.F.S. Grundtvig. Part 5, ‘The triumphator’, addresses Ørsted's discovery of electromagnetism, and Christensen disputes the claim that it occurred by chance. According to Christensen, Ørsted's first experiment with the Galvanic trough apparatus and magnetic needle may have been carried out spontaneously, but it was not a lucky accident:

Christensen compellingly establishes that Ørsted's experiment demonstrated what was Ørsted's long-held assumption of the interaction between electrical forces and a magnetic needle.

Reading Nature's Mind is a well-written and beautifully illustrated book. It is extraordinarily detailed and leaves the reader with a thorough understanding not only of Ørsted, but also of his contemporaries. However, the amount of detail is also its primary weakness. While immensely interesting, it is sometimes difficult to see how long passages of the book relate to Ørsted's work and life. In some instances, Reading Nature's Mind reads more like an introduction to modern European history than like a biography. Despite this reservation, Reading Nature's Mind is an excellent book that will remain the go-to biography on Ørsted for a long time to come.