As the chief of the Circus, Control somehow is more mysterious and calculating than Smiley, not even appearing in le Carré's first two novels. The chief's name is never given, instead operating behind the scenes in perfect fashion. Though only appearing briefly in Spy, Control's presence and force in the narrative cannot be understated. For such a commanding role, few could do a better job than Tilda Swinton, bringing out Control's scheming, ruthless nature. 

Alec Leamas, our hero, begins the novel as the leader of the failing West Germany Bureau of the Circus—le Carré's pointed name for the British overseas intelligence agency. He's called back to England only to be given one last mission: a highly dangerous undercover operation to take down enemy agent Hans-Dieter Mundt. Obviously, things don't go as smoothly as Leamas would like. For the lead, we think Warren Brown would excel given his tenure on Luther, where he showed an ability to keep calm under pressure and held his own against the likes of Idris Elba.

What's a spy thriller without a love interest? Before going undercover, Alec meets Liz Gold, an English librarian with ties to the Communist Party of Great Britain. The two fall in love, and when Alec embarks on his mission he warns Liz to stay away. You can guess how well that goes. Natalie Dormer, who most recently stole the spotlight on Game of Thrones, would be a fine pairing with Brown.

When our hero goes undercover, he collaborates with an East German agent named Fielder, who already suspects Mundt of being a traitor. The man is bright and idealistic, and becomes a close ally to Alec throughout his mission. We nominate Alexander Fehling, a talented German actor who could fully introduce himself to Western audiences in a breakout role.

Hans-Dieter Mundt is no slouch when it comes to villainous qualities. He's an ex-Nazi who upholds his anti-Semitic views and works essentially as a mercenary for the Communists. We'd love to hate Til Schweiger in the role, the German actor most well known for playing the feisty, barbaric Nazi killer Hugo Stiglitz in Quentin Tarantino's Inglourious Basterds (2009).

George Smiley is second only to James Bond when it comes to spy icons, and is about the total opposite of him. His thick, framed glasses, dry tone, and manipulative schemes are enthralling and frightening. Of course he plays a part in Alec's undercover mission, and of course he doesn't divulge all the details of his plan to our hero. Though he may be younger than most who portray Smiley, Sean Harris could make for a tremendous rendition of the intelligence officer, offering a sinister and brilliant performance worthy of Alec Guinness's former role.