Veteran foreign correspondent Luke Harding has reported from all over the world, but there’s one subject he keeps returning to: Russia. His latest book, “Shadow State,” offers a glimpse into the country’s ruthless intelligence services. In this podcast, he speaks to New Lines Magazine's Faisal Al Yafai about how he uncovered their activities, from social media trolling campaigns to mercenary black ops in Syria and Sudan. They discuss the challenges of reporting on such a secretive world — and the heroism of the Russian citizens working to expose it. Produced by Joshua Martin.