This book presents an analysis of the male supremacist ideology of the internet-based subculture known as the manosphere and examines the process of radicalization to violent extremism that occurs within the group. The manosphere is the online subculture comprised of several distinct groups who share a basic gender ideology that is misogynistic and anti-feminist in the extreme. The manosphere celebrates a toxic hegemonic masculinity that encourages sexual violence and portrays violence as an understandable response to a feminized culture that denigrates manhood. Evidence has shown that several recent cases of murder, mass murder, and rape involved offenders who participated in this subculture prior to engaging in their crimes. Through the use of quotes gathered directly from the websites and message boards frequented by individuals within the subculture, this book offers an in-depth analysis of the ideology of the manosphere, and the common attitudes, values, and beliefs promoted within the various groups that comprise the subculture. It also presents a theoretical perspective that may shed light on what draws men to these groups and the processes by which they become radicalized to the far right and violent extremism. This book will be of interest to scholars and students in criminology, sociology, and political science, and others interested in examining the manifestation and effects of the manosphere on crime and criminal justice.