Based on a large-scale survey, it is found that during the Cultural Revolution masses took part in the movements to either improve their social status or maintain their social positions. In the provinces immersed in class based struggles, there was strong relationship between faction alignment and family background. Nevertheless, in the provinces involved in non-class based sectarian struggles, the association between the two was nil. The social conflict school failed to notice the sectarian internecine fights among rebels while the political process school failed to pay attention to the fundamental social conflicts in China. The book summarize the lessons learned from the self destruction of the mass movements and point out pitfalls for the future social movements in China.