Understanding : Film Noir

“Between the Great Depression and the start of the
Cold War, Hollywood went noir, reflecting the worldly, weary, wised-up under
current of midcentury America. In classics such as Laura, Sweet Smell of
Success, and Double Indemnity, where the shadows of L.A. and New York pulse with
killers, corpses, and perilous romance, failure is not only a logical option but
a smart-talking seduction.” – Vanity Fair March 2007

Principally in film noir, it is the narrative and existential angst that drives a mostly male protagonist, who more often than not is the victim of a manipulative femme-fatale. 

“Noir is premised on the audience’s need to see failure risked, courted, and sometimes won; the American dream becomes a nightmare, one strangely more seductive and euphoric than the optimism it repudiates… Noir provided losing with a mystique.”

retrieved from : http://filmsnoir.net/what-is-film-noir#ixzz2EBluif2z