Shaul Katzir, Christoph Lehner, and Jürgen Renn, (eds.) Traditions and Transformations in the History of Quantum Physics (Berlin: Edition Open Access, 2013), 340 pp.

It is only a minor exaggeration to claim that modern physics is essentially quantum physics. Given the profound importance of the theory dating back to Max Planck, Werner Heisenberg and other pioneers, it is understandable that the historical development of quantum mechanics and allied sciences has been a prime concern of historians of physics since the 1960s. Although the field is very well explored, it is far from exhausted. It is still an active research area with several lacunae and unsolved problems. This is illustrated by the present volume, the outcome of a conference on the history of quantum physics that took place in Berlin in 2010 on the initiative of the Max Planck Institute for the History of Science.

Proceeding volumes are almost by definition faced with the problem of inhomogeneity and lack of coherence. After all, they consist of separate contributions that are generally of a high scholarly level but with little unity among them. This is also the case with the volume under review, where, to diminish the disunity, the editors have organized the 13 chapters under five headings, namely, From Classical to Quantum Physics, Quantum Mechanics in the Making, Extending the Framework of Quantum Physics, The Challenges of Quantum Field Theory, and Traditions and Debates in Recent Quantum Physics. Chronologically, it covers aspects from the period of the early 19th century (the so-called old quantum theory) to the rise of quantum-based nanotechnology a century later. The latter subject is covered by Christian Kehrt, who aims at contextualizing the history of modern nanotechnology, a field that he sees as a boundary object embedded in the history of earlier semiconductor physics.

As I see it, the primary value of the book is the collection of detailed and mostly novel case studies that, each in its own way, contributes to both a broader and deeper understanding of the historical development of modern physics. There is no common theme running through all the chapters, but several of them focus on relatively marginal actors and developments that are off the main road of the traditionally theory-oriented narrative. Thus, although Maria Göppert (or Göppert-Mayer) is one out of only two female Nobel laureates in physics, in the context of quantum theory she is a marginal figure. However, as Barry Masters points out, in her doctoral dissertation of 1930 she made an important contribution to quantum mechanics by calculating the probability for two-photon quantum transitions.

Another example of a marginal actor is the physical chemist Otto Sackur, who today is mainly remembered for the Sackur-Tetrode equation and whose work on the borderline between chemistry and quantum theory is analyzed in an informative chapter by Massimiliano Badino and Bretislav Friedrich. Sackur's approach was characteristically different from the one followed by, for example, Niels Bohr and Max Born, in so far that it was pragmatic and oriented towards concrete problems, in his case related to gases and chemical equilibrium processes. It was, as the authors express it, a mundane quantum physics coming from below. Results counted more than principles. This kind of approach, where quantum theory was seen as a tool for solving well-defined problems and exploring the boundary between quantum and classical physics, also appears as a theme in Marta Jordi Taltavull's chapter on optical dispersion in the period before quantum mechanics.

While the interaction between chemistry and quantum theory has been investigated in considerable detail by historians of science, the same is not the case with the relationship between engineering and quantum theory. Of course, quantum mechanics led to a new kind of solid state physics with important technological consequences (such as the transistor), but what about the influence of engineering theory and practice on the formation and development of quantum physics? Without dealing with the question in full, Kenji Ito addresses it in his chapter on the Japanese physicist Nishina Yoshio, who was trained as an electrical engineer and stayed in Europe through most of the 1920s. Ito argues convincingly that Nishina's original training in electrical engineering, and especially in circuit theory, prepared him advantageously for the research in quantum mechanics that in 1929 led to the important Klein-Nishina formula based on Dirac's relativistic theory of the electron. On the other hand, his work was not influenced by either Japanese culture or a particular Japanese style in science and engineering. On the contrary, Ito stresses that Nishina's work was similar to the kind of work pursued by his colleagues in Europe. Another Asian scientist included in the volume is the Chinese physicist Tsung-Sui Chang, who in the 1930s and 1940s visited Cambridge, England, where he worked on mathematical methods related to quantum field theory. The chapter on Chang, written by Yin Xiaodong, Zhu Zhongyuan and Donald Salisbury, provides information about Chang's contributions to theoretical physics and also about his education and life. (He died tragically in 1969, when he committed suicide after being persecuted by the notorious Gang of Four.)

Apart from the chapters already mentioned, the book includes contributions by Shaul Katzir (on early radiation physics), Dieter Fick and Horst Kant (on light atoms and light molecules), Daniela Monaldi (on quantum statistics), Dean Rickles (on early quantum gravity), Roger Stuewer (on nuclear fission), Adrian Wüthrich (on Feynman diagrams) and Olival Freire (on interpretations of quantum mechanics). While some of the chapters are highly technical, most are not and will be accessible also to readers without a solid training in physics. The book is clearly aimed at the small community of historians of modern physics and as such it is a welcome contribution to the scholarly literature.