Any reader (or listener) of stories about espionage and diplomacy might imagine a world populated by the characters of Ian Flemming and similar writers. John Le Carre doesn't write thrillers.He does however create a world where there is more often rivalry and conflict between personnel, government departments and international allies or as they are described in this audio book, "The Cousins".
To understand the plot the reader needs to be aware of Le Carre's earlier works - in particular, 'Tinker, Tailor, Soldier Spy'. This tale is populated with characters from the earlier work in particular George Smiley.
All Le Carre's novels are solidly constructed, even if the direction or theme seems to meander from time to time. To be honest I would have prefered a Cover-To-Cover Narration, but even in a BBC dramatisation it is well worth a listen.