Fictional CIA agent Sam Durell is the protagonist for all of the stories in this series. Though the publisher listed these as the “Assignment series”, it is just as well known as the “Sam Durell series". In later editions, the publisher also used “Sam Durell” in the blurb immediately after the front cover - For example, "Assignment Ceylon" has “This is number thirty-six of the famed Sam Durell novels—one of the bestselling suspense series in the history of publishing.” One consistent element is that all of the story titles started with the word “Assignment.”