How Rivalry Defines UsFootball, Tribalism, and the Boundaries of Belonging
Rivalry is not an optional extra in football.
It is one of the forces that gives loyalty its shape.
How Rivalry Defines Us is the third and final book in Thomas Calder's acclaimed trilogy on football loyalty, following It's In the Blood and You Don't Choose This Life. Where the first book explored how loyalty forms, and the second examined how it is lived through ritual and commitment, this final volume turns to meaning - and to the opposition that gives belonging its edges.
This book asks a difficult but essential question: who are we without them?
It explores how rivalry creates identity through contrast, how enemies are inherited before they are understood, and how opposition sharpens belonging rather than weakening it. From ritualised hostility and territorial ownership to the moral lines supporters refuse to cross, Calder examines rivalry not as mindless aggression, but as a deeply human structure that organises emotion, memory, and group identity.
Drawing on psychology, social identity theory, and lived supporter culture, the book also confronts modern football's growing discomfort with rivalry. As globalisation, branding, and digital culture soften traditional boundaries, long-standing fans are left with a sense that something vital is fading. Rivalries are diluted, repackaged, or displaced - and loyalty itself begins to feel thinner.
This is not a celebration of violence or hatred. Nor is it a nostalgic defence of football's worst excesses. It is a clear-eyed examination of why rivalry mattered, how it functioned, and what is at risk when the lines that once defined belonging begin to blur.
How Rivalry Defines Us completes a trilogy that traces football loyalty from formation, to action, to meaning - and leaves readers with a deeper understanding of why the game still matters, even when it becomes uncomfortable.
