War Machines: Transforming Technologies in the U.S. Military, 1920–1940, is not as broad as its title might suggest. Timothy Moy does indeed propose a broad thesis, that institutional culture plays a large, though seldom acknowledged, role in technological innovation. But he addresses only two very particular case studies of military innovation between the world wars. The longer reviews the Army Air Force's development of the technology for precision bombing; the shorter examines the U.S. Marine Corps's development of the technology for (...) amphibious assault. What primarily shaped these innovations were, in Moy's view, the particular cultures of the air force and marines and their internal politics rather than the more commonly cited technical or industrial imperatives.The book is divided into two parts, each of four chapters, plus an introduction and a conclusion . As we might expect of a study derived from a Berkeley history of science dissertation, War Machines rests on a reasonably solid research base. The two stories are told separately, however, and differ significantly in both structure and documentation. Part 1, “Precision Bombing,” alternates chapters on doctrine and technology. Chapters 2 and 4 follow the air force adoption of strategic bombing as a mission to win independence from the army. Judging by the endnotes, both chapters rest chiefly on secondary sources and are less analytical than assertive. Chapters 3 and 5 trace the air force effort to find the bombsights and bombers that its self‐chosen mission required. These chapters offer a more extensively documented and persuasive narrative than those on doctrine, although the two are not very well integrated. Part 2, “Amphibious Landing,” in contrast, integrates doctrine, training, and technology in a single narrative. It begins with the marines adopting advanced base defense and amphibious warfare to define missions that would sustain institutional independence, then follows the interaction of doctrinal evolution, training exercises, and technological development. These chapters are based much more heavily on archival research than those in Part 1.Moy is a fine writer, but he sometimes lapses into phrasemaking at the expense of explanation. Referring to the air force as a “high‐tech” organization, for instance, he claims that “the airmen's institutional self‐image as futuristic and gallant knights of the sky shaped the vision of strategic bombing they articulated and embraced. Daylight bombing grew out of this high‐tech culture” . How bombing squares with a “knights of the sky” self‐image he never explains. Nor does he ever fully address the specifics of one of his major categories, high‐tech versus low‐tech innovation. This becomes all the more troublesome when he extends the distinction by characterizing the air force as high tech, the marines as low tech. Quite apart from the anachronistic usage, this contrast tends to become more label than analysis.However well chosen Moy's cases, two seems a slender base to sustain his thesis. One feature of his argument that I find particularly problematic is the almost complete absence of internal opposition. Neither airmen nor marines spoke with one voice about the choice of a single mission to define their service. Moy mentions the advocates of pursuit aviation only in passing, for instance, and is completely silent about any dissidence among marines. This places him in the company of a long line of historians and social scientists who have studied controversies over military innovation exclusively from the viewpoint of those perceived to be on the winning side. In his conclusion Moy does briefly discuss the alternatives each service might have chosen; but however well done, it is too little and too late. (shrink)