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) and You 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.

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).

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).

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.

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.

Detective-Mystery Films are usually considered a sub-type of crime/gangster films (or film noir), or suspense or thriller films that focus on the unsolved crime (usually the murder or disappearance of one or more of the characters, or a theft), and on the central character - the hard-boiled detective-hero, as he/she meets various adventures and challenges in the cold and methodical pursuit of the criminal or the solution to the crime. The plot often centers on the deductive ability, prowess, confidence, or diligence of the detective as he/she attempts to unravel the crime or situation by piecing together clues and circumstances, seeking evidence, interrogating witnesses, and tracking down a criminal. See also AFI's 10 Top 10 - The Top 10 Mystery Films and Filmsite's related Greatest Plot Twists, Spoilers, and Surprise Endings.

Film Sub-Genres: Listed below are some of the most common and identifiable film sub-genre categories, with descriptions of each type or category. These are identifiable sub-classes of the larger category of main film genres, with their own distinctive subject matter, style, formulas, and iconography.

Stars: Daniell Edwards, Sami Darr and Anna Bård

Thriller and Suspense Films: These are types of films known to promote intense excitement, suspense, a high level of anticipation, ultra-heightened expectation, uncertainty, anxiety, and nerve-wracking tension. Thriller and suspense films are virtually synonymous and interchangeable categorizations, with similar characteristics and features.

One of the earliest 'thrillers' was Harold Lloyd's comic Safety Last (1923), with the all-American boy performing a daredevil stunt on the side of a skyscraper. The haunting and chilling German film M (1931) directed by the great Fritz Lang, starred Peter Lorre (in his first film role) as a criminal deviant - a child killer. The film's story was based on the life of serial killer Peter Kurten (known as the 'Vampire of Dusseldorf'). Edward Sutherland's crime/horror thriller Murders in the Zoo (1933) from Paramount starred Lionel Atwill as a murderous and jealous zoologist. And various horror films of the period, The Cat and the Canary (1927), director Rouben Mamoulian's Dr. Jekyll and Mr. Hyde (1931) with Fredric March, and The Bat Whispers (1930), provided some thrills.