Explores the fascinating phenomenon of how small, seemingly insignificant events can lead to large, unexpected changes in complex systems. Drawing on examples from physics, biology, sociology, and economics, the book delves into the concept of critical mass—the tipping point at which a system undergoes a dramatic transformation. Ball examines how complex interactions between individual components of a system can lead to emergent behavior, where the whole becomes greater than the sum of its parts. Through engaging examples and accessible explanations, the book reveals how critical mass plays a central role in everything from the spread of diseases and the dynamics of social networks to financial markets and natural disasters. Ultimately, Critical Mass offers an insightful look at the science of interconnectedness and the unpredictable nature of complex systems.