Why do football fans decide to support one club over another in cities where intense, deep-seated rivalries exist?What makes them choose: family ties, geography, politics, religion or perhaps race? 'Rivals Game' author Douglas Beattie spent two years discovering what lies at the heart of Britain's greatest derbies. Beattie takes the reader to the matches that have long been seen as passionate, divisive and vitally important to the entire cities in which they are played. These are the games that have a history of violence, feuding, social unrest and bigotry. But what is the truth about their origins and how does the enmity, so often displayed by supporters and gleefully by the media, manifest itself in an era which sees top clubs funded by billionaire chairmen and awash with TV revenue?