Delectable tidbits of literary journalismThe Literary Journalists, edited by Norman Sims. New York: Ballantine Books. 339 pp. $8.95 (paperback).

''The difference between literature and journalism,'' Oscar Wilde is reported to have said, ''is that journalism is unreadable and literature is not read.'' Like many a Wilde witticism, this one contains just enough truth to earn a laugh. Nonetheless, setting aside the troubling question of who outside the classroom reads literature, it might be argued that in the past 20 years, especially, a fair number of American writers have demonstrated that journalism, far from being unreadable, can be so well written and so literary as to render the traditional distinctions between literature and journalism all but irrelevant.

As its title indicates, Norman Sims's collection of recent journalistic writings rests contentedly on this assumption. The sticking point, of course, is the word ''literary.'' Exactly what does it mean to say that a piece of writing is literary or merits the presumably superior label of literature?

One answer to this ultimately unanswerable question was suggested by the ''new journalists,'' whose advent in the mid-1960s ushered in the recent age of literary self-consciousness among journalists. Given the right kind of reporting , writers like Tom Wolfe and Gay Talese argued, a journalist could appropriate any of the techniques used by fiction writers, up to and including stream-of-consciousness and omniscient narration.

The new journalism, as Sims points out in his introduction, is no longer new. Gradually the phrase has given way to ''literary journalism,'' a much broader term (if the selections in this book are any guide) that includes journalistic writing that does not rely principally on the tools of the novelist or short-story writer.

This makes it much more difficult to draw a line between literary journalism and ordinary, well-written journalism, and a number of the pieces that Sims, a journalism professor, has selected seem more ordinary than literary, including several whose chief merit is their journalistic ability to take the reader inside a profession or place usually closed to the general public - the work of a surgeon, the life of a fast-track computer executive, the privileged comings and goings in New York's famous ''21 Club'' restaurant.

Ernest Hemingway, a man who worked both veins, once said that literature, as opposed to journalism, opened to the reader ''a fourth and fifth dimension'' of human experience. A number of the pieces in ''The Literary Journalists'' would seem to pass this helpful if somewhat vague test: for instance, Jane Kramer's profile of a Texas cowboy, a piece that delves far below the surface of the standard journalistic profile to convey, with considerable feeling, the fears and frustrations of a middle-aged man who finds himself on the fringes of society.

''The Literary Journalists'' does not advance as convincing an argument for the literary possibilities of journalism as it might have. Where, for example, are Capote and Mailer, certainly the most literary of the contemporary writers who have ventured into journalism? But it does remind us how sophisticated journalism can be, and how, at its very best, it can measure up to Ezra Pound's judgment of literature as ''news that stays news.''