Featuring British master-spy George Smiley, it is the third and final novel of the "Karla Trilogy", following Tinker Tailor Soldier Spy and The Honourable Schoolboy.

[1] George Smiley is called out of retirement to investigate the death of one of his old agents: a former Soviet general, the head of an Estonian émigré organisation based in London.

Vladimir realises that Maria was used to provide a false identity for an unknown young woman, a ploy associated with KGB spymaster Karla, and that this is probably an unofficial operation.

Smiley consults dying former Circus researcher Connie Sachs, who identifies the second man as Oleg Kirov, also known by the cover name "Kursky".

Smiley flies to Hamburg and tracks down Claus Kretzschmar, an old associate of Leipzig and owner of the night club where the photograph was taken.

The transcribed tape of Kirov's confession to Leipzig shows that Karla is secretly diverting funds to a Swiss bank account using a commercial attaché named Grigoriev, of the Soviet Embassy in Bern.

The letter details Karla's illegal activities and offers him defection to the West and protection for Tatiana, or elimination by his rivals in Moscow Centre.

[2] One review speaks of the book's "purposefully quiet, slow, downright claustrophobic austerity", through which emerges "perhaps the greatest variety, texture, and integrity ever bestowed upon a series character".

Le Carré portrays all those involved in espionage, on whichever side, as flawed people, and it is their human weaknesses which interest him and keep the narrative moving.

As one critic notes of this novel, "Ultimately Smiley's people are all those who choose humanity over ideology and individuals over institutions".