Defense innovation is the transformation of ideas and knowledge into new or improved products, processes, and services for military and dual-use applications. It refers primarily to organizations and activities associated with the defense and dual-use civil-military science, technology, and industrial base. Included at this level are, for instance, changes in planning, programming, budgeting, research, development, acquisition and other business processes. The period between the two world wars offers a rich set of cases for examining defense innovation. These include the development of armored warfare, strategic bombing, close air support, carrier aviation, amphibious warfare, and radio and radar. Whereas others have focused on military innovation in the interwar period, the focus of this brief is on defense innovation in general, andthe development of tanks in Britain, the United States, and Germany in particular.