What is the setting of A Coffin for Dimitrios by Eric Ambler?

The story begins in Turkey and leads Latimer to Greece and France. Latimer is an Englishman, and the foreign setting makes the story of Dimitrios exotic. More than that, Latimer is a stolid, average person living in a world where drug smugglers, assassins, and spies do not exist. Latimer's only involvement in crime is fictional. When he travels into Dimitrios's world, he is traveling into an underworld, a criminal world that is completely foreign to Latimer.