A WRITER FRIEND of mine asked, after he had read my thriller in manuscript, why I had written it. "With just a couple of more turns you could have made a real novel of it," he said.

"I was teaching myself how to write a novel," I answered.

He thought about that, then nodded, satisfied: "Good answer."

I thought it was. After all, I was known, if at all, as a writer of nonfiction. I had done four books on subjects more or less literary, together with a metric ton of journalism of all kinds. Entry into the house of fiction is notoriously difficult for writers of my background. What I said probably suggested I was sneaking into it by a side door. My friend, a novelist, understood that. He certainly accepted it.

But what I told my novelist-friend was, like so much of what we utter, only part of the truth. I had the sneaking suspicion that I had actually written a novel. The book under discussion is a private eye story. I refrain from calling it a mystery because there's not much mystery to it. I said it was a thriller; perhaps the less specific term, crime novel, is best of all. But whatever name you use, I've read a lot that fit into that category -- genre fiction, they call books like that in the trade, not-quite-novels.

But that's just it, you see: The crime novel, at its best and perhaps merely at its better, is a form of fiction like any other, and not some lesser order of escapist literature fit only to pass empty hours with. There are certainly other forms of the novel that are accepted into the mainstream by critics and not dammed off and made to flow alongside in separate channels. To cite just a few: the academic novel (see Lucky Jim, Randall Jarrell's Pictures from an Institution and the works of Malcolm Bradbury and David Lodge); the novel of the love affair (it must end unhappily -- as do The Unbearable Lightness of Being and Alexander Theroux's recent, underrated An Adultery -- or be dismissed as mere romance); and the macho-challenge novel (Deliverance and The Flight of the Phoenix and a lot of war novels in between). These forms have their conventions, and within these forms many individual novels show certain similarities, plot to plot and character to character. Why should they be accepted and the crime novel rejected?

It wasn't always so. Its defenders are quick to point out that Crime and Punishment is quintessentially a crime novel and The Brothers Karamazov is a mystery of sorts. And wasn't Dickens writing The Mystery of Edwin Drood when he died (only to leave its solution to audiences at the Broadway show de-based upon it)? And how many of Joseph Conrad's novels are fundamentally thrillers? Let's see, there's Victory, Lord Jim, Nostromo, and stretching a bit, The Secret Agent, Under Western Eyes, Heart of Darkness -- actually, just about all of them.

But something happened that rather quickly consigned the crime novel in all its forms to its present low estate. In fact, two things happened. For one, there was James Joyce's Ulysses. Quite rightly hailed as a masterpiece from the moment of its publication in 1922, it was the most talked-about book of its time. But for years, due to the ban placed upon its importation and publication as pornography, it was more talked about than read. Its full impact was somewhat delayed -- but ultimately tremendous. What Joyce had done was to take the commonplace events of a single day and inflate them with myth and some of the most magnificent prose ever written to create an epic of the everyday. Because of his powerful example it eventually became not merely permissible but virtually requisite to write about the ordinary. The large events of the crime novel came, finally, to seem vulgar -- at least in those university classrooms with the long tables where creative writing is taught. There, the end product has become the minimalist novel -- Ulysses stripped bare of myth, certainly without the glorious prose, and with pure ciphers in place of characters -- the very essence of the mundane.

Then, also, by the time Ulysses was published the crime novel had taken a wrong turn and was well on its way to a dead end. It had become the detective story. Poe, they say, started it all with his C. Auguste Dupin stories. But with Arthur Conan Doyle's fictions dealing with the brilliant Sherlock Holmes, the detective novel became chiefly an English enterprise. Detection was entirely cerebral. The only violence in such stories was that minimum necessary to provide a body or two for the detective -- whether Lord Peter Wimsey, Hercule Poirot, Father Brown or the blind Max Carrados -- to solve the mystery and announce at the end whodunit. Neither in settings (garden parties, resort hotels, isolated islands), nor in details of execution did these "classic" mysteries bear any relation to criminal realities in England or elsewhere.

THIS SORT of detective novel never became very popular with American writers (although it certainly did with American readers). S.S. Van Dine followed the formula slavishly and enjoyed some popularity in the '30s. And Rex Stout also owed something to the English; only the beloved wise guy, Archie Goodwin, saved Stout's Nero Wolfe mysteries from becoming as mannered and cerebral as Agatha Christie's. But no, the Americans did the English one better: they invented a whole new form, which has become the modern crime novel.

Informed readers may have caught echoes of Raymond Chandler in my description of the English garden-party mystery. In his essay, "The Simple Art of Murder," he praised Dashiell Hammett as the writer who freed the mystery from such unrealistic conventions. That was generous of Chandler, and no doubt true as far as it went, for Hammett was a pioneer. But who wrote the Ur-Hamlet anyway, and why should it matter? It is from the work of Raymond Chandler himself, and not Hammett, that the modern American crime novel derives.

He was, first of all, twice the writer Hammett was -- and a very good one by any standard. His dialogue was crisp, often funny, and believable. His descriptive passages and his ability to create mood were unsurpassed, at least among writers in his time and place: Nobody caught the feeling of Los Angeles the way he did, and few have done it as well since. He proved, in other words, that good writing and realism were not inimical to the mystery. He wanted desperately to be taken seriously as an artist. He should have then -- and should be today.

Ross Macdonald always acknowledged his debt to Chandler, even though Chandler had some unkind things to say about Macdonald's first Lew Archer mystery, The Moving Target. Imitation may be the sincerest form of flattery, but those imitated seldom feel flattered. Chandler may have felt threatened by Macdonald, an equally good writer, for the disciple eventually garnered all the serious praise and recognition that the old master longed for.

Macdonald himself has had his imitators -- Collin Wilcox, T. Jefferson Parker and Jerimiah Healy come to mind -- but if pressed, the best writers in the field today would swear allegiance direct to Raymond Chandler. Who are we talking about here? Why, the modern masters of the crime novel -- Elmore Leonard, Robert B. Parker, Donald Westlake, Tony Hillerman, Patricia Highsmith, and probably George V. Higgins (in his early books) and Lawrence Sanders, as well.

It is an interesting group. Only a couple of them have written bona-fide mysteries. And when detecting is done, as it is in books by Robert B. Parker and Tony Hillerman, it is performed without superhuman feats of ratiocination. It takes place as in real life-proceeding by blundering luck and common sense, with the aid of informants, and with confidence that somehow, by the last chapter, the truth will out. (Raymond Chandler once wrote that the best mystery would be one that could be read without the last chapter -- i.e., without the solution and for its novelistic virtues alone.)

W.H. Auden, himself a devotee of the English garden-party mystery, perceived that "Chandler is interested in writing, not detective stories, but serious studies of a criminal milieu, the Great Wrong Place, and his powerful but extremely depressing books should be read and judged not as escape literature but as works of art," So it is, too, with Chandler's followers. Many of them have written from the point-of-view of the criminal, or at least those on the periphery of crime. As Auden suggested of Chandler, their subject is the criminal milieu. They write crime novels.

ARE THEY NOVELISTS? Of course they are. They cannot be dismissed simply because the incidents they describe are inherently more interesting than those in what are accepted as mainstream novels. In fact, successful crime novels depend far less on the violence of their plots than they do on their characters -- just as it is and should be with novels of any kind.

Today the crime novel, in all its forms, proceeds most surely and satisfactorily from character. The conventions of the mystery are observed in the detective novels, certainly. But often that's of secondary importance. When readers remember Tony Hillerman's latest, A Thief of Time -- and his Navajo reservation stories are the kind you do remember -- they may not recall whodunit, rather they'll remember that this was the one in which Lt. Joe Leaphorn mourned the passing of his wife Emma. Do people read Robert B. Parker's Spenser novels for their intricate plots and ingenious solutions? Certainly not -- or if they do, they are invariably disappointed. No, they read them because they like Spenser and are fascinated by his complicated relationship with Susan Silverman and with his black sidekick, Hawk. They read Sara Paretsky because they are quite taken with V.I. Warshawski; they like her style. Will Matt Scudder, Lawrence Block's alcoholic detective, make it through this case without falling off the wagon? You read each new novel to find out. James Crumley's benighted heroes, Milo Milodragovitch and C.W. Sughre, have difficulties similar to Scudder's; and what's more, in Crumley's latest, Dancing Bear, Milo-Milo started snorting cocaine, bad business for a private eye. On and on. Today's detectives are about as far removed from gentleman sleuths as reality from fantasy. Such as they are, we recognize them and identify with them.

As for the more open novels of the criminal milieu, well, just take a look at those of Newton Thornburg; they tell you how it is ordinary men and women become involved in situations they can and sometimes can't handle. John Katzenbach's In the Heat of the Summer could serve as an object lesson to all reporters regarding the danger of getting too close to an an ongoing investigation. And often, too, in the novels of Ross Thomas we see bystanders pulled quite unwillingly into the center of the action.

The appeal of such recurrent themes is easy to explain. All of us feel close to crime today. It's no longer something we merely read about in the newspapers. Most of us know victims, and some of us may even have been victimized ourselves. That may be why crime fiction is the biggest and fastest-growing category in publishing today. Readers no longer look for escape when they pick up a crime novel. They read it for the same reasons they read novels of any other kind -- to be entertained, certainly, but also to learn something about the real world, and those, good and bad, who inhabit it. Doesn't that make the crime novel just another form of fiction rather than a separate genre? I think it does.

Bruce Cook's novel "Mexican Standoff" will be published this fall.