This part introduction presents an overview of the key concepts discussed in the subsequent chapters. The part provides an overview of how a wide range of individual difference variables predict belief in conspiracy theories. It focuses on ‘hot’ motivation and emotion and addresses how various motivations and emotions that people have shape their belief in conspiracy theories. The part examines the role of intergroup relations and conflict in conspiracy beliefs about social groups. It also provides an overview of the behavioural and psychological consequences of conspiracy theories, illuminating the need for interventions in society. Physiological measures would be useful in the study of conspiracy theories because they provide information about processes that people cannot control. Conspiracy theories are everywhere in society and large groups of citizens believe them. Social psychologists seek to understand conspiracy beliefs by examining the role of both individual and situational factors, and by examining the societal implications of conspiracy theories.