Written by global, multidisciplinary experts, Responsibility for Extreme Beliefs and Behaviors explores the relation between responsibility and extreme beliefs and behaviors. The book is divided into three parts. The first part examines the issue of who or what is responsible, such as individuals, groups, the community, or even structural factors. It also addresses how individual responsibility relates to group responsibility. The second part concerns agency and various kinds of responsibility. It studies to what extent we can ascribe agency, both moral and epistemic, to extremists, and explores how epistemic agency depends on cognitive and affective capacities, self-knowledge, and intellectual self-trust, self-esteem, and self-respect. Moreover, it examines which environments foster extreme beliefs and behaviors and whether extremists and terrorists can be described as evil and how that bears on responsibility. The third and final part investigates when responsibility attributions are appropriate. It looks at various excusing and exculpating conditions of individual or group responsibility for extreme beliefs. It studies indoctrination and how much room it leaves for responsibility, and considers factors such as experiencing peer pressure, being in an epistemic bubble or echo chamber, and living in a society dealing with fake news and propaganda, and to what extent such factors can provide an excuse. In doing so, it takes not only the legal but equally the moral and epistemic dimensions of responsibility into account and how these relate to one another.