The Vienna Police Dept. has a special unit that is assigned solely to patrol the city's intricate sewer system, as its network of interlocking tunnels make great hiding places for criminals on the run from the law, stolen property, drugs, etc. The "actors" playing police officers in the film were actually off-duty members of that unit.

Orson Welles worked one week on this film.

During meetings between Graham Greene and Carol Reed with David O. Selznick, Greene was less than impressed with Selznick, who had (according to Selznick's own son) "become something of a parody of himself". Greene later mocked Selznick's dependency, at that stage, on the drug Dexedrine, better known as "speed". Coincidentally, Reed also became hooked on Dexedrine whilst shooting the time-consuming film. Both Reed and Selznick were operating on as little as 2 hours of sleep a day.

A huge fan of the film, Martin Scorsese wrote a major thesis on it whilst in film school. He got a B+ for it, his tutor remarking "Forget it, it's just a thriller".

When the film was initially distributed in America, David O. Selznick replaced the narration at the beginning (a necessity to explain the very unusual status of Vienna in the aftermath of World War II, when the film was set), originally done by Carol Reed himself, with a narration read by Joseph Cotten, in character as Holly Martins. Nearly eleven minutes of film was cut out in Selznick's version, including all references in the original cut to Cotten's Holly Martins being an implied alcoholic and anything else that portrayed him as a less than heroic figure.

The frequent use by director Carol Reed of Dutch angles to portray uneasiness and tension in the characters earned him a gift from his crew at the end of filming: a spirit level.

Somewhat apocryphal stories abound regarding Carol Reed discovering musician Anton Karas while scouring Vienna bars and nightclubs. Reed actually heard Karas playing at a production party and insisted the Austrian zither player come to Reed's hotel room and record songs to use for the contract. Later in production, Reed realized he wanted to use Karas' music for the whole film and flew Karas out to London to record the score. Karas became a top-selling musician thanks to the film and opened a nightclub called "The Third Man" in Vienna, which he ran to the end of his days.

During the shooting of the film, the final scene was the subject of a dispute between Graham Greene, who wanted the happy ending of the novella, and Carol Reed and David O. Selznick, who stubbornly refused to end the film on what they felt was an artificially happy note. Greene later wrote: "One of the very few major disputes between Carol Reed and myself concerned the ending, and he has been proved triumphantly right."

Director Carol Reed originally wanted James Stewart for the role of Holly Martins; producer David O. Selznick insisted on Joseph Cotten, who was under contract to Selznick's production company at that time.

Carol Reed went to great lengths to capture the atmosphere of the beleaguered city on film, and he was helped along by city officials and ordinary inhabitants. On nights when rain was unavailable to give the cobblestone streets the appropriate glistening sheen, for example, the city would provide a fire brigade to wet things down. Reed also incorporated many local residents into the film as extras such as the often glimpsed balloon seller.

Carol Reed had three separate film units working most days of production: a daytime unit, a nighttime unit and a sewer unit. Reed insisted upon directing each unit, resulting in him working 20 hour days.

David O. Selznick insisted the filmmakers use Alida Valli for the female lead. Actually, Carol Reed and Alexander Korda were happy with the choice. Selznick became dissatisfied that Reed had Valli wear more plain clothes, wanting her to look glamorous and beautiful throughout. Reed won out on this aspect, due to the support of Korda.

Ranked #5 on the American Film Institute's list of the 10 greatest films in the genre "Mystery" in June 2008.

Orson Welles starred in a British radio series ("The Adventures of Harry Lime" [broadcast in the United States as "The Lives of Harry Lime"]) 1951-52) based on the early adventures of his character in this film.

The tunnels featured in this film are part of the Wienkanal, which channels the Wien River through central Vienna out to the Danube River. The main tunnel is the huge arched structure through which the river flows a distance of about 1.6km. The gated side passages are connections to a wet weather sewer overflow, and the chamber with the balconies is the overflow point. The spiral staircase is one of 6 exits from the main culvert. Tours are run through the system on a daily basis. Events are occasionally held down the tunnels in commemoration of the film and its characters.

The most popular film in the UK in 1949. The Austrians, however, did not care for it.

Orson Welles initially refused to do the sewer sequences because he was convinced the bad air would give him some disease. Carol Reed claimed there was nothing to worry about as the smell was a result of disinfectant, not excrement. According to Reed, the apprehensive Welles didn't believe him.

Although David O. Selznick theoretically produced, the rest of the crew hated him and his ideas (he suggested once to Graham Greene that the film be called "Night Time in Vienna").

In one shot in the Wienkanal, a security officer passes by a wall with the engraving "O5," which was the secret symbol of the Austrian resistance against Nazi occupation. ("O5" represents "OE" or "Ö," the first letter of "Österreich," the native name for Austria.)

The film was released in America by Criterion on the Blu-Ray disc format, but was almost immediately discontinued due to Criterion losing the rights to the movie, which then went back to Studio Canal, the previous owners. As such, the Blu-Ray release from Criterion has quickly become a collector's item.

The future director John Glen was working in the editing department at Shepperton Studios when the film started production. He had a similar build to Joseph Cotten and was enlisted to supply the sound of his footsteps in post-production sound dubbing. He watched a continuous loop in the Westrex theatre and memorized the exact speed of Cotten's pace before dashing outside to a stairwell with a hard surface where the sound of his walking was recorded.

David O. Selznick wanted Robert Mitchum to star as Holly Martins, but the actor's arrest for marijuana possession made this impossible.

There are many oblique angles in the movie, where the camera is tilted so the horizon line is not horizontal, to give a feeling of awkwardness and uneasiness. After he saw the movie, William Wyler, a friend of Carol Reed, sent him a spirit level with a note: "Carol, next time you make a picture, just put it on top of the camera, will you?"

This film tops the "BFI 100", a list of 100 of "the best British films ever" compiled by the British Film Institute (in 1999/2000). Paradoxically, it is also included (at #57) on the American Film Institute's Top 100 American films" list compiled in 1996.

Bernard Lee (Sgt. Paine) played James Bond's superior M in the first eleven Bond films from Dr. No (1962) to Moonraker (1979) while Robert Brown (British Military Policeman in Sewer Chase) succeeded him in the role in Octopussy (1983), A View to a Kill (1985), The Living Daylights (1987) and Licence to Kill (1989).

The failure of the original copyright holder to renew the film's copyright resulted in it falling into public domain, meaning that virtually anyone could duplicate and sell a VHS/DVD copy of the film. Therefore, many of the versions of this film available on the market are either severely (and usually badly) edited and/or of extremely poor quality, having been duped from second- or third-generation (or more) copies of the film.

Since Orson Welles refused to be filmed in Vienna's sewers, his close-ups were shot in London Film Studios, while a body double was used for wide shots. The resulting footage is said to be about 85% Vienna, 15% London.

This was meant to be the first of a series of collaborations between mega-producers David O. Selznick and Alexander Korda. However, as the production grew difficult, they decided to take it one film at a time. Ironically, due to the success of the film, since both producers were at each other's throats for the credit for the film, they never collaborated again.

The first British production to be largely shot on location. With its preference for real locations and real local people as extras, it's also Britain's first attempt at the neo-realistic style that Italian directors like Luchino Visconti and Roberto Rossellini were making so popular at the time.

The original script included a return appearance by Basil Radford and Naunton Wayne, playing Captain Carter and Captain Tombs respectively, similar to Charters and Caldicott, the two English cricket enthusiasts who first appeared in Alfred Hitchcock's The Lady Vanishes (1938), and later in Carol Reed's Night Train to Munich (1940). However, the two characters were streamlined into the role of Mr. Crabbin, played by Wilfrid Hyde-White.

Initially cautious about Karas' music, Selznick sent this telegram to his VP from London. "November 25, 1949 TELEGRAM to Daniel T. O'Shea [Executive VicePresident, Selznick Productions] ...Cannot commence to tell you sensation caused by Karas's zither music in The Third Man. It is rage of England and has already sold more record copies than any other record in entire history of record business in England. It is widest-played dance music in England... Ads here use "Hear Harry Lime Theme," etc. in type dwarfing all other billing. It is one of those unpredictable, tremendous sensations that I cannot expect any of you to understand who have not been here. Entirely unrelated newspaper articles and editorials, even on politics, constantly refer to it. Inevitably, this success will be repeated America if we are prepared for it. We should be able to make fortune out of this music". Regards, David By the time Selznick released the film in the U.S., in February 1950, the "Harry Lime Theme" was already a sensation. He capitalized on this by including the tag line "Featuring the Famous Zither Score by Anton Karas...He"ll have in you a dither with his zither!" in the ad campaign and trailers.

Graham Greene's only original screenplay.

Paul Hörbiger couldn't speak a word of English and had to learn his lines phonetically.

Harry Lime's character name may be derived from Graham Greene's own name. Henry=Harry Graham Greene (Green)= Lime. Others say he chose the surname because it "reminded him of the quicklime where murderers were buried."

By all accounts Carol Reed was a relatively slow director, completing only a few shots or set-ups per day. Time was all-important during the Vienna shooting, however, because the location filming needed to be completed before the late winter snows set in.

Having scored a notable success pairing director Carol Reed with writer Graham Greene the year before with The Fallen Idol (1948), producer Alexander Korda was very keen to replicate the pairing.

In the AFI book "Private Screenings" critic Roger Ebert cited this as his favourite film. He later listed it in his piece "Ten Greatest Films of All Time".

Creator and executive producer of Breaking Bad (2008) and Better Call Saul (2015), Vince Gilligan, has stated this is his favorite film. The film's theme is used in an episode of Better Call Saul

In May 1999, it was announced that John McTiernan would be directing a modern day remake set in New York with Liam Neeson and Ewan McGregor starring. It failed to materialise, presumably much to the delight of famed screenwriter Buck Henry, who on hearing of The Big Sleep (1978) said, "Enough is enough, if anyone tries to remake "The Third Man", I'll take a shotgun to them".

In Vienna the film has a permanent slot in one of it's oldest cinemas. It is playing three times a week in the famous "Burgkino".

Joseph Cotten re-created his role in the Lux Radio production of "The Third Man" with Evelyn Keyes playing Alida Valli's role. Orson Welles was not in this radio play.

Noël Coward was David O. Selznick 's first choice to play Harry Lime.

In the scene where a man kicks a soccer ball that bounces where a character is hiding, Les Bennett was used. Les Bennett was a footballer in Tottenham Hotspur at the time, and his skills were used to make sure the ball hit its mark.

Bernard Lee was second choice for Sgt. Paine. The actor who was first choice was not hired because of billing issues.

"Theater Guild on the Air" broadcast a 60 minute radio adaptation of the movie on January 7, 1951 with Joseph Cotten reprising his film role.

Graham Greene referred to the film as a "comedy thriller".

Whilst the film boasts no less than two future M's in the James Bond films (Bernard Lee and Robert Brown), it also includes the brief appearance of Geoffrey Keen as a British Military Policeman. He was later to play the Minister for Defence in the films of the Roger Moore era. The production staff also contains two future Bond directors, John Glen and Guy Hamilton.

Included among the American Film Institute's 1998 list of the Top 100 Greatest American Movies.

Though Graham Greene never disclosed whom the character of Holly Martins was based upon, Criterion's latest released version contains Philip Kerr's insight into it, (very) possibly being based upon Robert Bruckner, who was this film's producer/screenwriter, against whom Greene 'nursed a grievance'. Amongst the (many) reasons cited by Kerr, is Holly Martins 'being an author of low-brow western novels, including one entitled Oklahoma Kid, (which viewers will notice Baron Kurtz carrying a copy of Oklahoma Kid, by Holly Martins). Bruckner was a screenwriter, whose work included many westerns, amongst them; The Oklahoma Kid.

Visible throughout the film is the "Hotel Sacher." Famously known for being first to serve one of Vienna's and now Europe's most famous desserts; the Sachertorte.

Film debut of Robert Brown.

Included among the "1001 Movies You Must See Before You Die", edited by Steven Schneider.

The film is included on Roger Ebert's "Great Movies" list.

Princess Margaret was said to be a big fan of the theme music.

The Baltimore Waltz, written by playwright Paula Vogel, quotes from the movie about Switzerland and the cuckoo clock.

In the "special features" of the Blu-ray release of The Third Man, the commentary reveals how Carol Reed, cleverly brightened his nighttime shots of Vienna's streets by the wetting the cobblestones and shining studio lights off the wet surfaces. In one shot, men are seen in the background hosing down the street with what appear to be fire hoses. Whether this inclusion is incidental mise-en-scene remains unclear.

This film is part of the Criterion Collection, spine #64

Janez Lapajne has stated this is most probably his favorite film.

Orson Welles evaded production assistants and assistant director Guy Hamilton whilst traveling in Europe when he was supposed to be on location filming in Vienna. During Welles' unexpected absence, Carol Reed had to film around him, getting numerous spectacular shots in the sewers seen in the finished film. Numerous body doubles for Welles were used, included Hamilton, who was made to wear an over-sized hat and padded coat to approximate Welles' larger size. Reed himself doubled for Welles' hands when they reach through the sewer grate. When Welles finally arrived, he was 2 weeks late.

Cary Grant was considered for the part of Harry Lime. Conicidentally, Grant was a regular lunchtime visitor to the set of the film when the shooting returned to London sound-stages.

The scene showing the waning moments of Harry Lime's life in which he extends his fingers futilely towards freedom through a grate in the sewer was suggested to the director by Orson Welles. The hands actually used in that shot belong to director Carol Reed.

Rumors have long since been widespread that Orson Welles wrote all of Harry Lime's dialogue and even that he took over the direction of his own scenes. Everyone involved, including Welles himself, have always insisted that the film was directed by only Carol Reed. Welles did claim that he wrote most of Lime's dialogue, which is also a fabrication. The extent of Welles' contributions were Lime's grumbling about his stomach problems (which were improvisations) and the famous "cuckoo clock" spiel at the end of the ferris wheel scene.

Once he finally arrived in Vienna, Orson Welles refused to film various scenes in the sewers. Due to his protests, various sets replicating the Vienna sewers had to be constructed by Alexander Korda on sound-stages back in England.

The ending was the subject of contention during production. Surprisingly, Graham Greene, known for his bleak, depressing stories, wanted the film to have a "happy ending", with Holly Martins embracing Anna Schmidt after Lime's funeral; whereas David O. Selznick, known for his love of "Hollywood endings", advocated that Anna should ignore Holly after the funeral. Carol Reed agreed with Selznick and the sad ending was used. Reed, however, felt insecure about the length of the nearly 2-minute shoot he filmed where Martins waits for Anna and she walks by him without acknowledging his presence.

The huge Ferris wheel that Martins and Lime ride on in the Prater was erected in 1897. Sigmund Freud claimed to have used it to induce seasickness in patients whilst experimenting with cocaine as a treatment.

David O. Selznick was resistant to Carol Reed's idea of casting Orson Welles as Harry Lime, since Selznick had labeled Welles as "box office poison".

Orson Welles is on screen for only about five minutes.

After giving his talk to the book club, Holly Martins escapes from the police through an attic room containing a cockatoo (referred to as "a parrot" by Martins). There is a brief shot which includes a painting of a nude seen over Martins' shoulder. The nude's pubic hair can be clearly seen, so this shot's appearance in a major release of the period represents a very rare lapse by film censors.

Graham Greene based the character of Harry Lime on British double agent Kim Philby, who was Greene's superior in the British Secret Intelligence Service.

Orson Welles said that when he agreed to play Harry Lime, he was offered either a straight salary or a percentage of the profits. Welles chose the salary, but he later regretted it because the film went on to become such a huge hit, the percentage was ultimately worth far more than the salary.

When assistant director Guy Hamilton was negotiating with the owners of the flat which overlooked the square where Orson Welles would be famously hiding in a doorway, he was getting nowhere with them when he told them that the film starred Welles, Joseph Cotten and Alida Valli. It was only when he mentioned in passing that local star Paul Hörbiger was also in the film that they fell over themselves to offer up their apartment.

In Vienna there are canal tours called "Der Dritte Man -Tour" which visit the exact places where the scenes of Harry Lime being chased by the police were shot.

During the Dritte Mann tour in Vienna, they have a rat behind a plexiglass barrier, and the tour guide says, "Oh, look! A rat!"