Roberto Lalli's Building the General Relativity and Gravitation Community during the Cold War provides a unique and unexplored history of the formation of general relativity as a field under a single common organization during the Cold War period. With the exception of short episodes, the field of general relativity is largely seen as removed from the Cold War and the military–industrial complex of the mid-twentieth century. However, Lalli's work problematizes this understanding by focusing on how physicists and mathematicians in the field of general relativity built an international community of relativists and created one the most sought-after and lucrative fields of physics while navigating the geopolitics of the Cold War. Prior to the creation of the relativity field, its specialists were dispersed across small groups with only loose affiliations to the general categories of physics and mathematics. Lalli's work shows us that the politics of organizing conferences and a unified society for the relativity field were greatly intertwined with the politics and international relations of the Cold War.

For those not familiar with the history of the rise and adoption of general relativity, Lalli provides a concise introduction to the periods of the development and adoption of general relativity explored in the relevant scholarship, particularly that of Jean Eisenstaedt and Clifford Will, and Lalli's own work with Alexander Blum and Jürgen Renn. These periods include, first, the rise of general relativity (1907–1915); second, the formative period (1915–c.1925); third, the period of the low-water mark (c.1925–c.1955); fourth, the renaissance (c.1955). Important to the present work is Blum et al.’s position that the renaissance period for general relativity can be seen as the product of an ‘interplay’ between internal and external factors of the field (p. 18). These authors define internal factors as the ‘resilient theoretical framework provided by general relativity’ and external factors as the ‘working conditions for physicists in the post-World War II period’ (p. 18). With this in mind, the crux of Lalli's argument is that the renaissance era should be understood through its transformation from a dispersed and fragmented state to ‘a real community’ of those theorizing and researching under the common label of ‘relativist’ (p. 36, original emphasis). Thus underlying the entire work is Lalli's interest in whether the institutionalization of a field can also coincide with the scientific progress of that field.

Often the renaissance period of general relativity is explained as coinciding with the occurrence of two conferences – the Bern conference (1955) and the Chapel Hill conference (1957) – but serendipitous events which played a role in the planning and culmination of the Bern conference are in focus in Lalli's work. The Bern conference, which occurred during the fiftieth anniversary year of Einstein's publication of his theory of general relativity, holds importance within the history of the field of general relativity because it was seen as transforming the ‘social perception of the epistemic status of the field … by the simple fact that different knowledge products were shared in the same space and time by a community of people who, prior to this event, did not perceive themselves as belonging to any community’ (pp. 48–49). This conference also coincided with the start of the post-Second World War support for peaceful coexistence and the related promotion of international scientific organizations by various countries with the intent of appropriating each other's technological and scientific advancements, using science as a bargaining chip in foreign policy, or using scientific collaboration for propaganda. This period also occurred shortly after Stalin's death, which allowed for Soviet physicists to engage more freely in international science organizations to the benefit the field of general relativity due to expertise in Eastern Bloc countries.

Of noted importance throughout the work is physicist André Mercier's efforts as the organizer of the Bern conference and his decision to place the Bern conference in his neutral home country of Switzerland. Although Mercier had not yet conducted any major work within the relativity field, Lalli argues that his choices for the structure and invitees of the Bern conference were imperative for the formation of a relativity community. For example, Mercier provided that individuals could only attend if invited and these invitations were sent directly to the national academies, which provided a feeling of exclusivity that was appealing to scientists and theorists in general, but also to Communist governments which had the practice of selecting those who would attend international conferences at their respective national academy level instead of democratically from within the fields’ members.

In providing a wholly new perspective of the general-relativity community during the mid-twentieth century, Lalli argues that the formation of the International Committee on General Relativity and Gravitation (ICGRG) ‘was strongly related to the developments of international political relations during the Cold War and its structure mirrored the geopolitical scenario at the time’ (p. 54). What does this mean? Lalli explains that those who attended were limited, member countries were also limited, and the locations of the meetings affected those would could attend, further limiting participation. Each of these limitations was a direct product of the Cold War geopolitical situation.

With respect to meeting locations, Soviet physicists were not permitted to attend the famous Texas symposia (1963) in the United States, during which the notion of relativistic astrophysics was solidified, due to strained relationships between the United States and the Soviet Union and other Eastern Bloc countries. Further, when an ICGRG meeting was planned to be held in Tbilisi, Georgia, in the Soviet Union, Lalli explains that Israeli physicists were not invited due to the Six Day War (1967), which was seen as largely anti-Semitic by some of the members of the ICGRG and blurred the group's express separation from the politic climate. Further, Mercier made the drastic move of advising all the ICGRG members not to attend the meeting in Tbilisi in light of the invasion of Czechoslovakia by the Soviet Union, Poland, Bulgaria, the German Democratic Republic and Hungary in 1968. Lalli describes such a move as drastic because prior to this period the ICGRG leadership had avoided all mention of the political climate and such a move placed the international aspect of the organization in precarity. During the 1970s, the ICGRG decided to host a meeting in Israel. Immediately, Vladimir Frock, a prominent Soviet physicist of the period, described such a move as a ‘political action’ because Soviet physicists would not be granted visas due to conflicts between Israel and surrounding countries and their alliance with the Soviet Union. Such political difficulties continued, as Lalli explains, when an American contingent tried to democratize the ICGRG in the early 1970s; this was met with protest from Eastern Bloc countries because, as mentioned above, delegates to international meetings were selected by the national academies of the respective countries, particular Eastern Bloc countries, so such a move to a democratic selection could possibility lead to the inability of physicists from Eastern Bloc countries to participate. Through this history Lalli expertly shows that although it was a goal to operate the ICGRG without regard to politics, the geopolitical situation of the Cold War was difficult to avoid when trying to form an international community and host meetings at various sites between Europe and the United States.

In conclusion, Lalli shows that although the formation of the relativity community was intertwined with its Cold War political context, the field of general relativity had become a solidified and sought-after field within physics by the mid-1970s. Despite this political background, Lalli reminds us that this Cold War context provided benefits that general relativity was able to capitalize on – the relaxed East–West relations post-Stalin and the neutral launching site of Switzerland for the Bern convention.

In closing, do not forget to turn to the end of the work because Lalli provides a wonderful Appendix of each of the groups which formed this new relativity community.