To really understand the development of noir as a distinct literary form (distinct, I mean, from the whodunit or the procedural) you need to go back to the career of Elisabeth Sanxay Holding.
Along with folks like Cornell Woolrich and James M. Cain, Holding crafted tales of murder where the emphasis was on the perpetrators and the victims rather than on the heroic investigators. If most mystery fiction is about the reordering of chaos--setting right what has gone wrong, uncovering and punishing some aberrant evil--then Holding was far more interested in why people go wrong. Her characters are desperate or drunk or demented. Or all three.
In books like THE BLANK WALL, THE INNOCENT MRS. DUFF, NET OF COBWEBS, or THE GIRL WHO HAD TO DIE, Holding kept the emphasis on the dark interior lives of her characters. As much as someone like David Goodis, Holding traps us in the narrow, obsessive minds of her characters.
I have a new essay on Holding over at Criminal Element. Check it out and let me know what you think.