This espionage tale intricately unveils the complex nuances of a spy's profession. In crafting the storyline, le Carre skillfully withholds details, maintaining suspense for his audience. The Spy Who Came in from the Cold features a straightforward plot, is not cluttered with too many characters, and unfolds in a linear manner. Le Carre uses minimal description, yet his deep understanding of Germany shines through. The Wall, which frames the novel's beginning and end, is depicted with stark clarity and strength, almost taking on a life of its own.

Le Carre is a masterful linguist, especially adept at crafting dialogue that often feels like an overheard conversation. Through dialogue rather than description, characters reveal their true selves. Le Carre skillfully captures Liz's naive curiosity and unwavering commitment, Leamus's cynical disdain, and Mundt's shrewdness through their words. His sentences are concise and direct, with a vocabulary that is both precise and inventive.

The novel's greatest strength lies in the transformation it brought to the conventional espionage narrative. Unlike the devoted nineteenth-century characters loyal to their nations, le Carre introduces a shadowy figure, deeply unhappy and uncertain about his role. He portrays espionage as a harsh, cold, and bitter endeavor. With remarkable clarity and insight, he captures the political atmosphere of the 1960s and the profound postwar disillusionment.

As an espionage narrative, The Spy Who Came in from the Cold, along with all of le Carré's works—except perhaps The Naive and Sentimental Lover (1971)—fits into the tradition established by authors like Somerset Maugham, Arthur Conan Doyle, and particularly Graham Greene. However, le Carré has crafted a hero who is more restless and ambiguous. In the realm of literature, there are echoes of Balzac, Stendhal, Dickens (notably Bleak House), and Henry James in his writing. Joseph Conrad also stands as one of his influences, especially in his later works.

The Spy Who Came in from the Cold was effectively adapted into a film by Paramount in 1965. The movie featured Richard Burton, whose outstanding performance earned him an Academy Award nomination. Le Carre, however, has not been involved in the adaptation process of any of his works and typically stays uninvolved with them.