Our stories of industrial innovation tend to focus on individual initiative and breakthroughs. With Making Jet Engines in World War II, Hermione Giffard uses the case of the development of jet engines to offer a different way of understanding technological innovation, revealing the complicated mix of factors that go into any decision to pursue an innovative, and therefore risky technology. Giffard compares the approaches of Britain, Germany, and the United States. Each approached jet engines in different ways because of its own war aims and industrial expertise. Germany, which produced more jet engines than the others, did so largely as replacements for more expensive piston engines. Britain, on the other hand, produced relatively few engines—but, by shifting emphasis to design rather than production, found itself at war's end holding an unrivaled range of designs. The US emphasis on development, meanwhile, built an institutional basis for postwar production. Taken together, Giffard's work makes a powerful case for a more nuanced understanding of technological innovation, one that takes into account the influence of the many organizational factors that play a part in the journey from idea to finished product.