Parliament has lost interest, but Britons still devour books about Brexit. Those books tend to belong to one of two schools. One is the Great Man—or rather, inadequate boys—theory of history, exemplified by “All Out War”, by Tim Shipman. It argues that the divorce was propelled by the betrayals, blunders and petty feuds at the court of David Cameron, whose campaign was hopelessly focused on warning of economic disaster.