Nova: Imagine a war that has been raging for over forty years, yet most people have never heard of its most intense battles. It is a war fought in the shadows, on the high seas, and through secret backchannels. This is the world of The Twilight War, a masterwork of investigative history that reveals the secret conflict between the United States and Iran.

Nova: Oh, it is very much actual combat. David Crist, the author and a senior historian for the federal government, spent years digging through declassified documents and interviewing special ops veterans to prove that we have been in a state of undeclared war with Iran since the Carter administration. He calls it the Twilight War because it exists in that hazy space between peace and all-out conflict.

Nova: That is a great catch. David D. Kirkpatrick is a