This essay introduces articles in this “Science and Nationalism” issue (part 1) by capturing some of the themes they illuminate and issues they raise. It highlights postcolonialism, Cold War politics, and post–Cold War geopolitics as the context in which various, shifting relationships between science and nationalism developed in Korea, China, and Japan. The essay also urges further research into science and nationalism “in action,” that is, by critically investigating the dynamic process of the making of science and nationalism in the reciprocal mobilization of each other and by placing this process in the material, economic context.