This book examines the birth of punk in the UK and its transformation, within a short period of time, into post-punk. Deploying innovative concepts of 'critical mass', 'social networks' and 'music worlds', and using sophisticated techniques of 'social network analysis', it teases out the events and mechanisms involved in punk's 'micro-mobilisation', its diffusion across the UK and its transformation in certain city-based strongholds into a variety of interlocking post-punk forms. Nick Crossley offers a detailed review of prior work in this area, a rich exploration of new empirical data and a highly innovative and robust approach to the study of 'music worlds'.Written in an accessible style, this book is essential reading for anybody with an interest in either UK punk and post-punk or the impact of social networks on cultural life and the potential of social network analysis to explore this impact.