Leonard, called "Dutch," by his friends, after the baseball pitcher, was born in New Orleans in 1925, the son of a General Motors site locator. When he was 9, his family moved to Detroit, where he lived for the rest of his life. He attended the University of Detroit, and after a three-year navy stint, became a copywriter, writing fiction on the side.
His first published story, a western called "Trail of the Apaches," appeared in 1951 in the pulp magazine Argosy; his first novel, The Bounty Hunters, another western, appeared two years later. For most of the next two decades, Leonard stuck with westerns as he developed and honed the straightforward, anti-authorial style he'd later be acclaimed for. (Hollywood noticed and appreciated Leonard's gift for storytelling—and easily adaptable dialogue—early: Three movies were made from Leonard stories in the 1960s.)
But by the end of the 1960s, the market for westerns had dried up. In 1969, he published The Big Bounce, his first crime novel; over the next five decades, Leonard would write another 40, many sharing characters (or at the very least, names) and a Detroit setting. As many as half were turned into movies. By the end of his life Leonard was praised by both fellow genre writers and the more traditional literary establishment; called "the Dickens of Detroit," he demurred: "I was called the Dickens of Detroit. Simply because it was alliterative. I wouldn't have been the Dickens of Chicago."
It's true that Dickens is florid and sentimental and Leonard is terse and impossible to excite, but otherwise it's not a terrible comparison. Both men understood how important is that serious books also be funny—that humor doesn't undercut dramatic tension, but supports it and allows it to breathe. Both were masters of characterization (and of great, evocative character names). And both were great urban authors, concerned with and interested in the social relations of cities and settlements, and the movement between and among groups and classes.
This was Leonard's central concern: the codes and rituals of tribal membership, and the porousness of the border between groups, even those seemingly opposed. Hombre, his best western novel, is the story of a white man raised by Apaches who, on inheriting a parcel of land, is forced to navigate his way among a series of tribes to which he doesn't really belong (while on a fraught, besieged stagecoach ride, obviously):
The characters in Leonard's crime novels share with their western-novel antecedents not a particular relationship to law and order but a sense of professionalism—a deep knowledge of the practices and rituals, the codes and conventions of their given fields. His crime novels concern characters who exist on the edge of the law, in gray areas that block them from full membership in Team Good or Team Bad—bounty hunters, bail bondsmen, ex-cons trying to make good, sleazy lawyers, slightly corrupt police officers, all forming alliances, enemies, and romances between and across tribes—but all of them (the ones Leonard sympathizes with, at any rate) are professionals. In Killshot, the seasoned hitman Armand Degas takes a younger wannabe, Richie Nix, under his wing, imparting to him the rules of the trade:
Rules like this, professional guidelines gleaned from years of work and dedication, pervade Leonard's novels (in many cases thanks to his researcher of three decades, Sutter, who provided Leonard with background about the fields and trades his characters worked). Leonard, himself a consummate professional and a tireless worker who at his death was said to be finishing another novel, loved them—the hard-won details that set apart a dilettante from a master.
Which is why it's nice to see writers on Twitter and Facebook—many of whom have likely never read more than one of his books—sharing a piece Leonard wrote for the New York Times in 2001. It's—what else?—a set of rules for writing. "You might look them over," he suggests.