The introduction briefly examines the context of Zexiao in public junior high school admission in China. Then it explains data collection and data analysis in the book project. It introduces a conceptual framework to explain why and how the author interprets Zexiao as a social closure phenomenon by a discourse analysis approach. Also, it comprehensively introduces how the author utilizes a case study of practices in admission to public junior high schools in Community A to further visualize multilayered social closures among stakeholders in the same process. This section concludes with an outline of the chapters of the book.