The biblical adage that "if a house be divided against itself, that house cannot stand" remains sound theological advice. It is also essential counsel for any political party that aspires to win elections. When a party is riven with division, the public does not know what it stands for. Though both major UK parties have been subject to internal conflict over the years, the Labour Party has been more prone to damaging splits. The divide exposed by the Corbyn insurgency is only the most recent example in almost a century of destructive infighting. Indeed, it has often seemed as though Labour has been more adept at fighting itself than in defeating the Tory party. This book examines the history of Labour's civil wars and the underlying causes of the party's schisms, from the first split of 1931, engineered by Ramsay MacDonald, to the ongoing battle for the future between the incumbent, Keir Starmer, and those who fundamentally altered the party's course under his predecessor, Jeremy Corbyn.