The development of think tanks embodies, to a certain extent, the soft power of national governance. High-quality think tanks support scientific, democratic and law-based decision-making while increasing the channels of public participation in decision-making. They also effectively provide information supplies and talent pools for national development and social progress, which gives rise to a marketplace of ideas. Think tank science and engineering is a new discipline derived from the scientific development of think tanks. This chapter makes clear the concepts and connotations, functions and structure, and research content of this discipline.