This book, first published in 1989, examines how a seemingly trivial incident can act as a flashpoint for wider disturbances. It investigates the underlying causes, the immediate context of the events, and the communication between police and crowd that takes place within them. The authors’ findings are based on first-hand research into case studies of political demonstrations, community disorder and industrial picketing in South Yorkshire, UK over a five-year period. Wide-ranging in its approach, the book covers industrial relations, police-community relations, and questions of political representation and legal rights. The authors provide a novel theoretical analysis, drawing on both sociology and social psychology, which they apply to their own case studies and to other instances of disorder, from Grosvenor Square in 1968 to Wapping in 1986. They also consider the possible impact of new public order legislation, and the policy implications of their research.