Urban violence still has a peculiar standing within social and urban research. This book works to unpack the link between urban, violence, and security with three main arguments. The first is that urban violence is under-theorized because long-term theoretical problems with both of its elements ('urban' and 'violence'). The second is to answer these questions: (1) how can violence be conceptualized in a way that opens to an understanding of the specificity of urban violence? (2) What is the urban in urban violence? And (3) How can 'urban' and 'violence' be articulated in a way that makes urban violence a category with both analytical and strategic power? The third, and central, argument of this book is that, through a genealogy that articulates political economic and vital materialism, urban violence can ultimately be framed as a precise category shaped by three interlocking trajectories: the process of (capitalist) urbanization, the spatio-political project of the urban, and the concrete urban atmospheres in and through which the process and the project materialize, often violently so, in the urban.