What could be more unsettling than the steely look on Gene Tierney's face as she watches her young brother-in-law drown in Leave Her to Heaven? Or Barbara Stanwyck's voice in Double Indemnity as she coolly tells her lover that it is "straight down the line for both of us" in their plot to murder her husband. Though often thought of as primarily male vehicles, films noirs offered some of the most complex female roles of any movies of the 1940s and 1950s. Stars such as Stanwyck, Tierney and Crawford produced some of their finest performances in noir, while such lesser known actresses as Peggie Castle, Hope Emerson and Helen Walker made a lasting impression on moviegoers with their roles in the genre. These six women and 43 others who were most frequently featured in films noirs are profiled here, focusing primarily on their work in the genre and its impact on their careers. A filmography of all noir appearances is provided for each actress.