Film noir

Film noirDouble Indemnity is archetypal of film noir in almost every way we now conceive of this major film cycle (Studlar 398).
What are the main concerns and stylistic features of Film noir?
In Double Indemnity (Billy Wilder, 1944) select and analyze two or three scenes or shots that present the characteristics and implement the strategies of Film noir (use of and effects/meanings created by specific film techniques).