Book excerpt: In previous books, the author has investigated rivalry in the context of sport and non-sport settings. This book investigates how rivalry and group member behavior manifests in the setting of politics, religion, and sport, three settings of intense group member bias. Building on the author’s Hierarchy of Out-group Derogation (HOD) and Out-group Derogation Spectrum (ODS), it discusses the potential of common interests to drive out-group cooperation. The work ends with a call for future research to better understand how to decrease out-group derogation and negativity. Incorporating research from marketing, psychology, political science, and sociology, this book offers researchers in several fields a new understanding of how setting and group membership influences the ways people view and behave toward out-groups.