The importance of technological evolution for the conduct of warfare throughout history is a topic thoroughly explored in the literature. Yet Rational Fog succeeds in bringing a new contribution to this debate, namely by tracking the blurry line between reason and violence. Lindee argues that the historical confluence of scientific and military dominance is not a coincidence, but rather the product of the intimate relations between technical knowledge and warfare. To illustrate her point, she analyses different socio-technical systems and dynamics in a US context: the gun, the process of industrialization, the trenches and chemical weapons in World War I, the atomic bomb and the shifts in post-World War II research, the emergence of studies of the human mind for the purpose of conducting state violence, the Cold War technological advances, and the weaponization of knowledge. The latter refers to how experts from a wide number of academic fields (from physics to psychology, from chemistry to sociology) put their expertise at the service of empowering the state and causing violence. These are not mere stories of war; they are illustrations of the seismic social mobilization that war entails. Throughout history, military machines have been, in Lindee's words, extreme products of human intelligence, and the rich empirical material provided in the analysis of the different chapters leaves a deep sense of unease. That some of the world's most brilliant minds have been used to maximize violence – and that the pursuit of that violence has fomented scientific evolution – are unsettling realities. While today's concerns about automation and artificial intelligence are certainly well-placed, Lindee's book reminds us that these dynamics go far back in history. Hopefully, we can learn something from that.