Book excerpt: Following the Nationalist defeat on the mainland in 1949, Chiang Kai-shek and his followers retreated to Taiwan, forming the Republic of China (ROC). Tensions with the People’s Republic of China (PRC) focused on control over a number of offshore islands, especially Quemoy (Jinmen) and Matsu (Mazu). Twice in the 1950s tensions peaked, during the first (1954–55) and second (1958) Taiwan Strait crises. This small body of water—often compared to the English Channel—separates the PRC and Taiwan, and has been the location for periodic military tensions, some threatening to end in war. Today, relations between the ROC and PRC depend on quelling tensions over the Taiwan Strait. This work provides a short, but highly relevant, history of the Taiwan Strait, and its significance today.