This book examines key moments in which collective and state violence was used to invigorate racialised social boundaries around Mexican and African Americans in the United States, and in which they violently contested them. Bringing the often-ignored history of anti-Mexican violence into a common analytical framework with anti-black violence, it pays particular attention to constructions of manhood within key moments of social unrest and collective violence in the first half of the twentieth century. Using archival materials, the book thus examines how African and Mexican American men have been constructed as 'racial problems', investigating, in particular, their relationship with law enforcement and ideas about black and Mexican criminality. The book will be of interest to students in American studies as well as those interested in the sociology of racism and masculinity.