It is generally assumed that the current world is governed by individualism. However, this book shows that the need to belong to a group or a community is a relevant feature of modern social life. The power of belonging lies in its capacity to create an emotional bond that promotes a shared identity, making possible the loyalty and solidarity among the members of a given community. It is precisely this strong emotional dimension that allows belonging to act as a generator of political mobilization and, in extreme cases, provoke collective violence. The feeling of belonging, crucial in the construction of the individual identity, interacts with this in complex ways. This becomes evident in a special way when belonging is the consequence of a process of choice, thus implying a degree of personal commitment that the attributed or traditional forms of belonging lack. Thus, many who appeal to tradition often invoke an "invented tradition" that is not a mere reproduction of the past. As the author argues, tradition intersects with modernity everywhere. Among the topics analyzed from this new perspective stand out identity as a political instrument, the study of emotions and political mobilization, the return of authoritarianism and the rise of the new radical right, as well as the strength of the symbols and rituals of belonging, and the meaning of loyalty, the nation and nationalism.