Film Noir (literally 'black film or cinema') was coined by French film critics (first by Nino Frank in 1946) who noticed the trend of how 'dark', downbeat and black the looks and themes were of many American crime and detective films released in France to theatres following the war, such as The Maltese Falcon (1941), Murder, My Sweet (1944), Double Indemnity (1944), The Woman in the Window (1944), and Laura (1944). A wide range of films reflected the resultant tensions and insecurities of the time period, and counter-balanced the optimism of Hollywood's musicals and comedies. Fear, mistrust, bleakness, loss of innocence, despair and paranoia are readily evident in noir, reflecting the 'chilly' Cold War period when the threat of nuclear annihilation was ever-present. The criminal, violent, misogynistic, hard-boiled, or greedy perspectives of anti-heroes in film noir were a metaphoric symptom of society's evils, with a strong undercurrent of moral conflict, purposelessness and sense of injustice. There were rarely happy or optimistic endings in noirs. Classic film noir developed during and after World War II, taking advantage of the post-war ambience of anxiety, pessimism, and suspicion. It was a style of black and white American films that first evolved in the 1940s, became prominent in the post-war era, and lasted in a classic "Golden Age" period until about 1960 (marked by the 'last' film of the classic film noir era, Orson Welles' Touch of Evil (1958)).
Important Note: Strictly speaking, film noir is not a genre, but rather the mood, style, point-of-view, or tone of a film. It is also helpful to realize that 'film noir' usually refers to a distinct historical period of film history - the decade of film-making after World War II, similar to the German Expressionism or the French New Wave periods. However, it was labeled as such only after the classic period - early noir film-makers didn't even use the film designation (as they would the labels "western" or "musical"), and were not conscious that their films would be labeled noirs.
Very often, a film noir story was developed around a cynical, hard-hearted, disillusioned male character [e.g., Robert Mitchum, Fred MacMurray, or Humphrey Bogart] who encountered a beautiful but promiscuous, amoral, double-dealing and seductive femme fatale [e.g., Mary Astor, Veronica Lake, Jane Greer, Barbara Stanwyck, or Lana Turner]. She would use her feminine wiles and come-hither sexuality to manipulate him into becoming the fall guy - often following a murder. After a betrayal or double-cross, she was frequently destroyed as well, often at the cost of the hero's life. As women during the war period were given new-found independence and better job-earning power in the homeland during the war, they would suffer -- on the screen -- in these films of the 40s.
See this site's special tribute to Greatest Femmes Fatales in Classic Film Noir
Titles of many film noirs often reflected the nature or tone of the style and content itself: Dark Passage (1947), The Naked City (1948), Fear in the Night (1947), Out of the Past (1947), Kiss Me Deadly (1955), etc. Primary Characteristics and Conventions of Film Noir: Themes and Styles
The primary moods of classic film noir were melancholy, alienation, bleakness, disillusionment, disenchantment, pessimism, ambiguity, moral corruption, evil, guilt, desperation and paranoia.Heroes (or anti-heroes), corrupt characters and villains included down-and-out, conflicted hard-boiled detectives or private eyes, cops, gangsters, government agents, a lone wolf, socio-paths or killers, crooks, war veterans, politicians, petty criminals, murderers, or just plain Joes. These protagonists were often morally-ambiguous low-lifes from the dark and gloomy underworld of violent crime and corruption. Distinctively, they were cynical, tarnished, obsessive (sexual or otherwise), brooding, menacing, sinister, sardonic, disillusioned, frightened and insecure loners (usually men), struggling to survive - and in the end, ultimately losing.
Storylines were often elliptical, non-linear and twisting. Narratives were frequently complex, maze-like and convoluted, and typically told with foreboding background music, flashbacks (or a series of flashbacks), witty, razor-sharp and acerbic dialogue, and/or reflective and confessional, first-person voice-over narration. Amnesia suffered by the protagonist was a common plot device, as was the downfall of an innocent Everyman who fell victim to temptation or was framed. Revelations regarding the hero were made to explain/justify the hero's own cynical perspective on life.
Film noir films (mostly shot in gloomy grays, blacks and whites) thematically showed the dark and inhumane side of human nature with cynicism and doomed love, and they emphasized the brutal, unhealthy, seamy, shadowy, dark and sadistic sides of the human experience. An oppressive atmosphere of menace, pessimism, anxiety, suspicion that anything can go wrong, dingy realism, futility, fatalism, defeat and entrapment were stylized characteristics of film noir. The protagonists in film noir were normally driven by their past or by human weakness to repeat former mistakes.
Film noir films were marked visually by expressionistic lighting, deep-focus or depth of field camera work, disorienting visual schemes, jarring editing or juxtaposition of elements, ominous shadows, skewed camera angles (usually vertical or diagonal rather than horizontal), circling cigarette smoke, existential sensibilities, and unbalanced or moody compositions. Settings were often interiors with low-key (or single-source) lighting, venetian-blinded windows and rooms, and dark, claustrophobic, gloomy appearances. Exteriors were often urban night scenes with deep shadows, wet asphalt, dark alleyways, rain-slicked or mean streets, flashing neon lights, and low key lighting. Story locations were often in murky and dark streets, dimly-lit and low-rent apartments and hotel rooms of big cities, or abandoned warehouses. [Often-times, war-time scarcities were the reason for the reduced budgets and shadowy, stark sets of B-pictures and film noirs.]
Some of the most prominent directors of film noir included Orson Welles, John Huston, Billy Wilder, Edgar Ulmer, Douglas Sirk, Robert Siodmak, Fritz Lang, Otto Preminger, Henry Hathaway and Howard Hawks.
The females in film noir were either of two types (or archetypes) - dutiful, reliable, trustworthy and loving women; or femmes fatales - mysterious, duplicitous, double-crossing, gorgeous, unloving, predatory, tough-sweet, unreliable, irresponsible, manipulative and desperate women. Usually, the male protagonist in film noir wished to elude his mysterious past, and had to choose what path to take (or have the fateful choice made for him). Invariably, the choice would be an overly ambitious one, to follow the dangerous but desirable wishes of these dames. It would be to pursue the goadings of a traitorous, self-destructive femme fatale who would lead the struggling, disillusioned, and doomed hero into committing murder or some other crime of passion coupled with twisted love. When the major character was a detective or private eye, he would become embroiled and trapped in an increasingly-complex, convoluted case that would lead to fatalistic, suffocating evidences of corruption, irresistible love and death. The femme fatale, who had also transgressed societal norms with her independent and smart, menacing actions, would bring both of them to a downfall.
Cinematic Origins and Roots of Classic Film Noir:
The themes of noir, derived from sources in Europe, were imported to Hollywood by emigre film-makers. Noirs were rooted in German Expressionism of the 1920s and 1930s, such as in The Cabinet of Dr. Caligari (1920, Germ.) or Fritz Lang's M (1931, Germ.), Fury (1936) andYou Only Live Once (1937). Films from German directors, such as F. W. Murnau, G. W. Pabst, and Robert Wiene, were noted for their stark camera angles and movements, chiaroscuro lighting and shadowy, high-contrast images - all elements of later film noir. In addition, the French sound films of the 30s, such as director Julien Duvivier's Pepe Le Moko (1937), contributed to noir's development.Another cinematic origin of film noir was from the plots and themes often taken from adaptations of American literary works - usually from best-selling, hard-boiled, pulp novels and crime fiction by Raymond Chandler, James M. Cain, Dashiell Hammett, or Cornell Woolrich. As a result, the earliest film noirs were detective thrillers. Film noir was also derived from the crime/gangster and detective/mystery sagas from the 1930s (i.e., Little Caesar (1930), Public Enemy (1931) and Scarface (1932)), but very different in tone and characterization. Notable film noir gangster films, such as They Drive By Night (1940), Key Largo (1948) and White Heat (1949) each featured noir elements within the traditional gangster framework. The Earliest Film Noirs: In the 1940s
Many sources have claimed that director Boris Ingster's and RKO's Stranger on the Third Floor (1940) was the first full-featured film noir. The expressionistic film starred Peter Lorre as the sinister 'stranger' (cast due to his creepy performance in M (1931)), in a story about the nightmarish after-effects of circumstantial testimony during a murder trial. Others claim Orson Welles' masterpiece Citizen Kane (1941) was also an early and influential pre-film noir. 
The first detective film to use the shadowy, nihilistic noir style in a definitive way was the privotal work of novice director John Huston in the mystery classic The Maltese Falcon (1941), from a 1929 book by Dashiell Hammett. [Actually, Huston's film was not the first version - it had been directed earlier by Roy Del Ruth in 1931, starring Ricardo Cortez in the lead role.] It was famous for Humphrey Bogart's cool, laconic private eye hero Sam Spade in pursuit of crooks greedy for a jewel-encrusted statue, and Bogart's foil - Mary Astor as the deceptive femme fatale.Noir Duo: Alan Ladd and Veronica Lake
The acting duo of Alan Ladd and Veronica Lake was first teamed in the superb early noir thriller This Gun For Hire (1942)(with the tagline: "He's dynamite with a gun or a girl"). From the novel A Gun For Sale by renowned British novelist Graham Greene, the moody noir featured Ladd in a star-making role (his first lead role) as a ruthless, cat-loving, vengeful, unsmiling San Francisco professional hit-man named Raven working for a peppermint-candy loving fat man Willard Gates (Laird Cregar) and his wheelchair-bound Nitro Chemicals executive Alvin Brewster (Tully Marshall) - both double-crossers who were selling secrets to foreign agents (the Japanese). Ladd was paired with popular wartime pinup star Lake as nightclub showgirl singer Ellen Graham, his hostage (and unbeknownst to him working as a federal agent).Another Dashiell Hammett book of political corruption and murder was adapted for Stuart Heisler's The Glass Key (1942) for Paramount Studios - again with the duo of Ladd and Lake, and noted as one of the best Hammett adaptations. Ladd starred as Ed Beaumont, a right-hand man and political aide attempting to save his employer (Brian Donlevy) from a murder frame-up, while Lake played the seductive fiancee of the boss. The film was noted for the vicious beating given to Ladd by a crime lord thug (William Bendix).
The popular noir couple were brought together again in George Marshall's post-war crime thriller The Blue Dahlia (1946), with an Oscar-nominated screenplay by Raymond Chandler (the only work he ever wrote directly for the screen). Alan Ladd portrayed returning war veteran Johnny Morrison who discovered that his wife Helen (Doris Dowling) was unfaithful during his absence. When she turned up dead and he became the prime suspect, he was aided in the case by the mysterious Joyce Harwood (Lake) - the seductive ex-wife of his wife's former lover.
Orson Welles and Film Noir:
Orson Welles' films have significant noir features, such as in his expressionistically-filmed Citizen Kane (1941), with subjective camera angles, dark shadowing and deep focus, and low-angled shots from talented cinematographer Gregg Toland. Welles' third film for RKO, the war-time mystery Journey Into Fear (1943), was one in which he acted and co-directed (uncredited) - it was set in the exotic locale of Istanbul. The film's story was inspired by Eric Ambler's spy thriller about the flight of an American arms engineer (Joseph Cotten) on a Black Sea tramp steamer where he was threatened by Nazi agents intent on killing him. The complex The Lady from Shanghai (1948) - with its plot (from Sherwood King's novel If I Should Die Before I Wake), told about a destructive love triangle between Irish seaman Michael O'Hara (Welles himself), a manipulative Rita Hayworth as the platinum blonde-haired femme fatale Elsa (or Rosalie), and her husband Arthur Bannister (Everett Sloane). Its final sequence in a San Francisco "hall of mirrors" fun-house was symbolic and reflective of the shattered relationships between the characters, exemplified by a wounded O'Hara's last words: "Maybe I'll live so long that I'll forget her. Maybe I'll die trying." Welles' Mexican border-town B-movie classic Touch of Evil (1958) is generally considered the last film in the classic cycle of film noirs. It starred Charlton Heston as Vargas - a naive Mexican-American narcotics cop, Janet Leigh as his imperiled, honeymooning wife Susan, and Welles' own corrupt and corpulent local cop Hank Quinlan. The film also featured a comeback appearance by cigar-smoking bordello madam Marlene Dietrich, and a breathtaking opening credits sequence filmed in a single-take. Later, Welles' expressionistic noir and psychological drama The Trial (1962) was an adaptation of Franz Kafka's classic novel, with Anthony Perkins as Joseph K - a man condemned for an unnamed crime in an unknown country. More Definitive 40s Noirs:
Early classic non-detective film noirs included Fritz Lang's steamy and fatalistic Scarlet Street (1945) - one of the moodiest, blackest thrillers ever made, about a mild-mannered painter's (Edward G. Robinson) unpunished and unsuspected murder of an amoral femme fatale (Joan Bennett) after she had led him to commit embezzlement, impersonated him in order to sell his paintings, and had been deceitful and cruel to him - causing him in a fit of anger to murder her with an ice-pick. Director Abraham Polonsky's expressionistic, politically-subversive Force of Evil (1948) starred John Garfield as a corrupt mob attorney.British director Carol Reed's tense tale of treachery set in post-war Vienna, The Third Man (1949), with the memorable character of black market racketeer Harry Lime (Orson Welles), ended with a climactic shootout in the city's noirish underground sewer. And the nightmarishly-dark, rapid-paced and definitive D.O.A. (1949) from cinematographer-director Rudolph Mate - told the flashback story of lethally-poisoned and doomed protagonist Frank Bigelow (Edmond O'Brien), a victim of circumstance who announced in the opening: "I want to report a murder - mine." [It was remade as D.O.A. (1988) with Dennis Quaid and Meg Ryan.]
Sourced from wikipedia. 
