Book excerpt: Mark Colvin is a broadcasting legend. He is the voice of ABC Radio's leading current affairs program PM; he was a founding broadcaster for the groundbreaking youth station Double J; he initiated The World Today program; and he's one of the most popular and influential journalists in the twittersphere. Mark has been covering local and global events for more than four decades. He has reported on wars, royal weddings and everything in between. In the midst of all this he discovered that his father was an MI6 spy. Light and Shadow is the incredible story of a father waging a secret war against communism during the Cold War, while his son comes of age as a journalist during the tumultuous Whitlam and Fraser years and embarks on the risky career of a foreign correspondent. Mark was witness to some of the most world-changing events, including the Iranian hostage crisis, the buildup to the first Gulf War in Iraq and the direct aftermath of the shocking genocide in Rwanda. But when he contracted a life-threatening illness while working in the field, his life changed forever. Mark Colvin's engrossing memoir takes you inside the coverage of major news events and gently navigates the complexity of his father's double life.