Fictional CIA agent Sam Durell is the protagonist for all of the stories in this series and so while the publisher listed this as the "Assignment series" it is 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." The stories were written over a span of 28 years from 1955 to 1983 with each more or less being set in present time at the time it was written. When initially issued the stories were not numbered and the publisher showed the list of available stories in the "Assignment" series in alphabetical order though often the alphabetical list did not include all of the previous stories. Later re-prints numbered the stories based the order in which they were first published though the list of stories just before the title page was still in alphabetical order. The list is shown in numbered/published order here. Each story is a standalone work and while they can be read in any order reading them in the order given here will provide some continuity as there are occasional references to people or incidents from previous assignments.
Used availability for Edward S Aarons's Assignment Ceylon
April 1981 : USA Mass Market Paperback
August 1974 : UK Paperback