Christopher Andrew is Professor of Modern and Contemporary History at Cambridge University, a Fellow of the Royal Historical Society, in-house historian for MI5, former Visiting Professor of National Security at Harvard University, and guest lecturer at numerous universities. With Oleg Gordievsky, he published KGB - The Inside Story, the book that revealed the identity of the fifth man. He is also the author of The Defence of the Realm: The Authorized Official History of MI5. Professor Andrew is also a frequent presenter of BBC TV and radio programmes on history and world affairs.