It is common for family empires to eventually pass into the managerial hands of an outsider. Rarely does an heir later take back the reins. Yet that is precisely what is under way at Bertelsmann, a German media colossus. After more than 40 years of being run by a series of hired bosses, the company has signalled that one of two brothers descended from its founder will be its next leader. This is the latest surprising twist in a bizarre family saga.