This book is an in-depth study of the structure and leadership of the All-China Federation of Trade Unions -- the largest mass organisation which aims at representing the interests of the labouring class in the People's Republic of China. Special attention is paid to the relations between the union system and the Party and State, to find out the circumstances and factors which affect the roles and autonomy of unions in China. While the period of analysis starts from 1949, events before 1949 are summarised at the beginning of the book so as to provide a backdrop for the research into the contemporary scene.