In April 2011, Barcelona and Real Madrid faced each other four times in just 18 days: twice in Champions League semi- finals, once in La Liga, again in the Copa del Rey. Those 18 days descended into a strained, feverish period that defined an era for one of football s most intense rivalries: Pep Guardiola and Jose Mourinho. In The Duellists, Paolo Condo tells the story of the rivalry that encapsulated both the best and worst of modern football.