Although the genre of crime fiction has existed in continental and American literature since at least the nineteenth century, the particular form of it known as “hard-boiled” fiction reached its greatest popularity during the period of the 1920s through the 1960s. Critics point out that authors who shaped the genre during this era—especially Dashiell Hammett, Raymond Chandler, and Ross McDonald—reinvented the crime fiction style popularized by such predecessors as Sir Arthur Conan Doyle and Dorothy L. Sayers in several key ways. They placed their crime stories not in a rural setting, as was typical of earlier crime fiction, but in a sinister and forbidding urban environment. Perhaps most importantly, they introduced the figure of the tough-talking, brave, but also disillusioned and alienated private eye, who contrasted markedly with the intellectual type of detective exemplified by Sherlock Holmes. On the thematic level, hard-boiled fiction focused on the secrets, mental depravity, and human weakness that lead to crime, rather than on the swift restoration of law and order. Neither high literature nor pulp fiction, hard-boiled fiction was crafted to be accessible to the common reader, yet it also incorporated modernist themes and techniques. While some critics have denigrated hard-boiled fiction as nothing more than a lengthy puzzle, others have written about the genre as a tool for social commentary and a vehicle for discussing changing notions about justice, morality, and personal and civic virtues.
In novels such as Hammett's The Maltese Falcon (1930), Chandler's The Big Sleep (1939), James M. Cain's The Postman always Rings Twice (1934), and Mickey Spillane's I, the Jury (1947) and Kiss Me, Deadly (1952), the hard-boiled detective emerged as the major point of interest in the work. The individual detectives—Sam Spade, Philip Marlowe, Lew Archer, Spenser, and Travis McGee—became as famous as the authors themselves, and their personal journeys toward solving the crime in question took on more importance than the resolution of the plot. The hard-boiled detective's main traits were cynicism, toughness in difficult situations, and a wise-cracking sense of humor, but also a strong sense of morality, the desire to see justice done, and the willingness to be physically or emotionally wounded. Scholars have traced the evolution of this character type in later hard-boiled novels, such as those of Jules Feiffer, Richard Brautigan, and Thomas Berger. These later authors present a more complex view of evil, with lines sometimes blurred between victim and criminal, and with a private eye who is less certain of the justice of his or her mission or of the system he or she serves. Still, many common elements remain in later hard-boiled fiction: violent crime, an intricate and exciting plot, and a brave but vulnerable private eye in the center of the action.
There has been much critical interest in the hard-boiled novel since its beginnings, but especially from the 1970s onward. Critics John G. Cawelti, Larry E. Grimes, and Gary Levisi have examined the characteristics, development, and central role of the hero in hard-boiled fiction. The theme of evil in hard-boiled fiction is the subject of studies by James F. Maxfield and Frederick Isaac. Studies of the hard-boiled novel's style have also been popular—for example, of humor, by Isaac; of the influence of modernism, by Scott R. Christianson; and of naturalistic elements, by Michael Pettengell. Many critics of the 1980s and 1990s have focused on women in hard-boiled fiction, both as authors and as protagonists. Studies by Robert Sandels, Timothy Shuker-Haines and Martha M. Umphrey, and Priscilla L. Walton and Manina Jones have probed the ways in which hard-boiled fiction has been influenced by the emergence of such private eyes as Sue Grafton's Kinsey Millhone and Sara Paretsky's V. I. Warshawski.