Extremist Propaganda in Social Media: A Threat to Homeland Security presents both an analysis of the impact of propaganda in social media and the rise of extremism in mass society from technological and social perspectives. The book identifies the current phenomenon, what shall be dubbed for purposes of this book "Blisstopian Societies"-characterized in the abiding "ignorance is bliss" principle-whereby a population is complacent and has unquestioning acceptance of a social doctrine without challenge and introspection. In these subcultures, the malleable population self-select social media content, "news," and propaganda delivery mechanisms. By doing so, they expose themselves only to content that motivates, reinforces, and contributes to their isolation, alienation, and self-regulation of the social groups and individuals. In doing this, objective news is dismissed, fake-or news otherwise intended to misinform-reinforces their stereotyped beliefs about society and the world around them. This phenomenon is, unfortunately, not "fake news," but a real threat to which counterterror, intelligence, Homeland Security, law enforcement, the military, and global organizations must be hyper-vigilant of, now and into the foreseeable future. Chapters cite numerous examples from the 2016 political election, the Russia investigation into the Trump Campaign, ISIS, domestic US terrorists, among many other examples of extremist and radicalizing rhetoric. The book illustrates throughout that this contrived and manufactured bliss has fueled the rise and perpetuation of hate crimes, radicalism, and violence in such groups as ISIS, Boko Haram, Neo-Nazis, white separatists, and white supremacists in the United States-in addition to perpetuating ethnic cleansing actions around the world. This dynamic has led to increased political polarization in the United States and abroad, while furthering an unwillingness and inability to both compromise or see others' perspectives-further fomenting insular populations increasing willing to harm others and do violence. Extremist Propaganda in Social Media relates current Blisstopian practices to real-world hate speech and violence, connecting how such information is consumed by groups and translated into violent action. The book is an invaluable resources for those professionals that require an awareness of social media radicalization including: social media strategists, law enforcement, Homeland Security professionals, military planners and operatives-anyone tasked with countering combat such violent factions and fringes in conflict situations.