It serves as a sequel to le Carré's previous novels Call for the Dead and A Murder of Quality, which also featured the fictitious British intelligence organization, "The Circus", and its agents George Smiley and Peter Guillam.
[2] Le Carré's debut novel, Call for the Dead, introduced the characters George Smiley and Hans-Dieter Mundt.
He quickly establishes a link between the East German Secret Service and the deceased, and learns that Mundt, an assassin, killed the man after a misunderstanding between Fennan and their controller, Dieter Frey.
The Spy Who Came in from the Cold picks up two years later, where Mundt has had a somewhat meteoric rise to become the head of the Abteilung, because of his success with counter-intelligence operations against British networks, as well as a member of the Presidium of the Socialist Unity Party.
Hans-Dieter Mundt, a former low level Abteilung officer who murdered Samuel Fennan a few years prior, has risen to power in the counterintelligence section and systematically eradicates the network.
Instead, Control requests he stay in play for one final operation; a simulated defection to East Germany to frame Mundt as a double agent.
In exchange for his success, Leamas will retain anything he makes on the mission, a pension pot, and will receive official sanction to retire from the Service.
In order to attract the attention of East German intelligence, Control organises Leamas' demotion to the finance department.
Leamas is forced onto the dole, lives in a substandard flat, and eventually starts working in a run-down library around local CPGB secretary Liz Gold.
A few days later, he says goodbye, and takes the "final plunge" into Control's plan, getting arrested for assault and sentenced to three months in prison.
Leamas is gradually exposed to more senior officials within the Abteilung, during which he drops hints about ongoing payments to a double agent.
In their time together, both men end up regularly debating the philosophical distinctions between Leamas' pragmatism and Fiedler's idealism of life in the DDR.
It is then revealed, however, that Fiedler had also submitted an arrest warrant for Mundt, leading the East German régime to intervene and convene a court.
Liz, however, is shaken, and realises that her actions have enabled the Circus to protect their asset Mundt at the expense of the thoughtful and idealistic Fiedler.
[9] According to Jon Stock, writing in The Daily Telegraph: "The plot of The Spy Who Came in from the Cold is assembled with more precision than a Swiss watch.
The heartless way in which Alec Leamas is manipulated; Control's ruthless playing of Mundt and Fiedler; and of course the dramatic ending on the Berlin Wall, immortalised in the film starring Richard Burton.
"[10] In 1965, Martin Ritt directed the film adaptation, with Richard Burton as Leamas, Oskar Werner as Fiedler, and Claire Bloom as Nan Perry, a renaming of the character of Liz Gold.
It starred Rory Keenan as Alec Leamas, Agnes O'Casey as Liz Gold and John Ramm as George Smiley, directed by Jeremy Herrin.