Mind control has proven a popular subject in fiction, featuring in books and films such as The Manchurian Candidate (1959; film adaptation 1962) and The IPCRESS File (1962; film 1965), both stories advancing the premise that controllers could hypnotize a person into murdering on command while retaining no memory of the killing. As a narrative device, mind control serves as a convenient means of introducing changes in the behavior of characters, and is used as a device for raising tension and audience uncertainty in the contexts of Cold War and terrorism. Mind control has often been an important theme in science fiction and fantasy stories. Terry O'Brian comments: "Mind control is such a powerful image that if hypnotism did not exist, then something similar would have to have been invented: