Chapter 1 focuses on the evolution of Chinese Communist Party support for Chinese scientists’ involvement in international scientific organisations during the Chinese Civil War and the early years of CCP rule after 1949. It analyses the meanings, motivations, and manifestations of such CCP-supported activities before and after taking power through organisations such as the Chinese Association of Scientific Workers, which had significant domestic and international dimensions. In doing so, it charts the rise of on Chinese involvement in the World Federation of Scientific Workers (WFSW) across the first decade of the international organisation’s existence, from its founding in 1946 through to Beijing hosting the federation’s tenth anniversary celebrations in 1956. This first decade of Chinese involvement in the WFSW showed the CCP’s united front work paying dividends in building relations with scientists at home and abroad, providing a platform from which the People's Republic of China would pursue a range of other efforts at international outreach.