Julie Le Gac and Nicolas Patin have produced a valuable and laudable contribution to the continuing scholarly debate about the relationship between the twentieth century’s World Wars. They frame the World Wars of 1914–1945 as »central to the history of Europe, if not the world,« while probing their origins and courses to determine their relationship to each other. They are particularly interested in the question of causation – whether the wars have common causes and whether the first was the cause of the second. Le Gac and Patin ultimately conclude that the era can be seen as a functional whole because of the emergence of industrial nation-states as the main international actors creating an era of mass and industrial warfare. They further argue that, in general, the First World War was an accelerator rather than the cause of World War II.

This work has many strengths. First, it draws very heavily from recent French scholarship, making it an excellent starting point for scholars looking to integrate French scholarship into their work. The authors draw from a good subset of anglophone works both in translation and in English. Le Gac and Patin posit that now is a fruitful time for major syncretic works. They argue that the wave of new research sparked by the centenary of the First World War is insufficiently integrated into the cannon and that assimilating this new production will accelerate the evolution of multiple subfields. Thus, a syncretic work can, they hope, contribute to a shift toward a global history of the wars and toward a popular history which recovers the experience of marginalized and victimized people.

Using the concept of paradoxes as a device to sift similarities and differences, Le Gac and Patin conclude that the two World Wars are part of a common history of accelerating violence rooted in the pre-1914 European world order. These paradoxes reflected the unexpected, and often unintended, results of both structural processes and contingent choices. They pay close attention to the paradoxes created by the relationship between the goals and effects of innovation. They argue that military leaders, especially but not only Germans, embraced delimiting the practice of warfare with the goal of using greater violence (tactics and weapons) to save (their own people’s) lives by ending the wars sooner, but the effects were usually merely to enhance suffering and kill more people when the other side adapted to the new method and responded in kind.

The authors frame World War I, and to a lesser extent World War II, as a »European war« from »its distant origins to the crucial escalation of July 1914.« They argue that the wars’ decisive fronts were European and that the main results of the wars were the victory of the concept of the nation-state over imperial governance. Never-the-less Le Gac and Patin agree these were truly global wars, but – perhaps paradoxically – they were global while remaining intrinsically European. Their causes were concentrated in Europe and the work is focused within the traditional Berlin-Paris-London triangle with periodical emphasis on Russia. Although the Middle East and East Asia are not absent, events there are rarely presented as central to the book’s most important debates and do not disrupt its heavy focus on West-Central Europe. The most obvious example of the work’s European focus is that Chapter 6 (covering the interwar era) almost completely ignores Asia, mentioning Japan only in passing and declining to explore the constant warfare in China, the Northern Expedition, or either the KMT-CCP or ROC-Japan conflicts.

The work's focus on West-Central Europe is also clear based on the literature the authors draw upon. While it draws heavily on French scholarship and makes good use of English-language scholarship, Middle Eastern and Asian scholarship is largely absent and even Eastern European and Italian scholarship is underused – sometimes frustrating the work’s grand syncretic ambitions.

Despite its weaknesses, Guerres mondiales: Le désastre et le deuil 1914–1945 is a valuable contribution to the literature on the World Wars. Its broad explanation of multiple interpretations of the World Wars makes it unusually valuable. While many works test individual theories, Le Gac and Patin make testing theories their primary task. While eschewing grand analogies like the wars being a »new Thirty Years War,« they identify critical connections including: the centrality of the nation-state, mass war, industrialized war, and the totalization of warfare. This case-by-case analysis is highly nuanced and generous to the scholars they draw upon. The authors’ separation of mass and industrial warfare is particularly well-executed and valuable in showing that these two, often conflated, concepts shaped the wars in different ways.

They temper these similarities with key differences. They cast World War I as revolutionary, while denying that character to World War II. The centrality of the Nazis’ vision of a world remade around German racial purity raises questions about their claim, but they defend it by focusing on the survival of pre-World War II ideologies and the dominance of the nation state. They also argue that people – by which they seem to mean Europeans – remember the wars differently. Memory of World War I is dominated by soldiers and trenches while World War II »has no place« because it had so many and for World War II civilians move to the center of the war as targets, participants, and victims of war. (404–405). In World War I violence against civilians was common but was generally a byproduct of warfare (though the authors acknowledge exceptions including the Armenian genocide). In contrast, Le Gac and Patin believe the intentional targeting of civilians as an end of its own was rooted in pre-1914 European colonial practice and military theory, accelerated by World War I, expanded in the interwar period, and emerged as a dominant strain in war during World War II.

Paradoxically, the one of the volume’s limitations – its emphasis on parts of the wars that directly touched France’s experience – emerges as a key strength. By placing French scholarship at the center of the work and using France’s experience of the wars as a lens, Le Gac and Patin have crafted a highly valuable contribution to the literature: a great introduction to the recent wave of French scholarship on the World Wars that also raises challenging questions about how to interpret and periodize a critical moment in human history.