THE OXFORD COMPANION TO ENGLISH LITERATURE. Edited by Margaret Drabble. Oxford. 1,155 pp. $35.

LATE IN THE REIGN of George V, a retired civil servant named Sir Paul Harvey put in five years making the first of the many Oxford Companions. He knew things gentlemen were supposed to know, notably the Bible, the classics, and literature (English and French). The idea for a Companion to English Literature had come from an Oxford editor. It would put Oxford lore at the disposal of folk less systematically educated: "ordinary everyday readers," the preface said.

So if you were puzzled when someone in a Victorian novel got driven to the next town by a "Jehu," Harvey could explain how "Jehu" meant "a fast and furious driver, a coachman; in humourous allusion to 2 Kings ix. 20." Victorian jocularity was often Biblical.

And if -- I don't know where -- you managed to collide with "Aldiborontiphoscophornio," a cross-reference would send you to "Chrononhotonthologos," where you'd learn that Aldi. . . etc. was a character in Chronon . . . etc., a 1734 play by Henry Carey (cross-reference to Carey). Though not greatly wiser, still you have the relief of knowing that somebody knows.

But the Companion did not simply ease reading. You could find in it, alphabetically tucked away, essential lore about what you hadn't read, perhaps had no hope of reading: e.g. plot summaries of every Scott or Dickens novel, every Shakespeare play. Who wants those? A harried scribbler of term-papers, perhaps. They're present because the demon Completeness requires them. ("Completeness": a Demon in a book review, 1985, by Hugh Kenner.)

My copy of the 1932 edition was a gift from a teacher. I doubt if I've used it six times in 40 years. For what I needed, there were other books I could turn to with more optimism.

Yet Harvey stays in print, revised and rerevised. The British novelist Margaret Drabble, in her preface to the present fifth revision (a five-year labor like Harvey's) draws a long breath and tries to redefine its purpose. Alas, that's not definable. Though she quotes the old phrase about "ordinary everyday readers," I'm sure she can't help feeling that it means rather less than in 1932, when it could still designate worthy folk beyond the circle of leisured gentlemen with good libraries. Who, at present, by any criterion, is non-ordinary, non-everyday? Not Margaret Drabble, even. And she's edited, I'd guess, as if for herself. And here at last is in edition I expect to find useful.

Given that it's harder than ever to say what the book is for, what she and her helpers have achieved is a wonder of brisk and diligent attention. New entries, revised old entries, are tightly informative alike. Sir Paul in 1932 gave T.S. Eliot five lines. The new Eliot entry begins, correctly, "a major figure in English literature since the 1920s." It proceeds for 700 words of admirable summary with no fewer than 23 cross-references including Lear (Edward) and "dissociation of sensibility." I don't know how you'd do better in that space.

The revision of Harvey's old Bleak House entry is less drastic. It reproduces his summary of the plot verbatim; then adds that while once Bleak House seemed Dickens in decline, "Later readers, including G.B. Shaw, Chesterton, Conrad, and Trilling have seen it as one of the high points of his achievement." That is orienting in 1985, and in its context Shaw, Chesterton, Conrad, Trilling are a foursome to meditate on.

Making room for the new, Drabble has weeded ruthlessly, sensibly. Victorian jocularity being now remote, "Jehu" was no longer helpful, and he's gone. A lot more is gone on the same principle. (But the English love curiosities, and you'll be glad to know that "Aldiborontiphoscophornio" survives.)

Adieu, much trivial clutter. Take Harvey's first nine entries, from "A.E., see Russell; (G.W.)" to "Abbey Theatre, Dublin, see Yeats." The first of these, "A.E.", was a mistake for AE, so Drabble has moved it to its proper alphabetic place, seven pages on. The next six, from "A Beckett, Gilbert Abbott" (a forgotten Victorian cut-up) to "Abbassides" (a dynasty of caliphs) have all been ousted, and a good thing. That makes room for Aaron's Rod, the D.H. Lawrence novel, and "Aaroon the Moor," a Shakespeare villain Harvey sonehow missed. And "Abbey Theatre" no longer says "see Yeats," but gets 500 nuggety words on its own. A leaner half-page by far.

Some entries show unexpected sprightly writing. The Heart of the Matter evokes "an area of 'Greeneland,' characterized by intense heat, vultures, cockroaches, rats, heavy drinking, corruption, and a painful struggle to maintain faith." Sir Paul Harvey was never vivid, nor sardonic.

WELCOME new categories have come in: detective fiction, science fiction. But a queer one too: composers. Who'd think to look up Mozart in a Companion to English Literature? Well, he had English connections. Mozart, it seems, was a young Austrian who visited London at 8, was received three times by George III, and wrote two symphonies "in Ebury Street." Alas, he "never came to England again." But he "certainly knew some Shakespeare," and one-third of the entry wonders what he might have done with The Tempest if he'd ever gotten round to setting a libretto based on it.

The entry on Beethoven is no less eccentric. The gibe used to be that Italian encyclopedias defined their criteria for admission via some Italian connection. That camel now has its nose in the Oxford tent.

Connoisseurs of the Oxford tradition of rank error (mildly exemplified by the dots in Harvey's "A.E.") will be happy to see it alive. Harvey had named the hero of Joyce's Ulysses as "Leopold Blum." His excuse, in those days of censorship, could have been that he'd never seen a copy.

And Drabble, though she's put Ulysses right (with "Bloom," but also with two questionable details), has us browsing no further than the letter "B" before we stumble on Mabel Beardsley, to whom, we read with amazement, W.B. Yeats "dedicated his sonnets Upon a Dying Lady."

But Yeat's sequence won't answer to that at all. It is not "dedicated" to anybody, (though, true, Mabel Beardsley's dying did inspire it). Nor does it contain a "sonnet" of any description. Here I see no excuses at all; Upon a Dying Lady has been accessible in London for 66 years.

Elsewhere Eliot's Sweeney Agonistes is dated 1932, some eight years too late. W.C. William's Poems (1909) were not "Imagist"; not only had Imagism not been invented, the poems in that fugitive book were incompetently, embarrassingly old fashioned: sonnets, even! Nor was Pound's Cathay based on "transliterations'" of Chinese; no one can transliterate a script that uses no letters. We're told too that in 1970 Pound published Drafts and Fragments of Cantos CX to XCVII. Anyone handy with Roman numerals will read "110 to 97" and spot a glitch. Yes. Read "CXVII."

And so on; not omitting a stumble on the very threshold, where Oxford acknowledges "the painting on the jacket, A Lady Reading by Gwen John," though the jacket displays nothing of the kind.

Proofing errors? Production errors? Mostly. Don't blame Margaret Drabble, whose labors and judgment have been (apart from those composers) heroic. Blame something that's happened since Sir Paul Harvey's day, an exponential increase in the complexity of book production, and a corresponding decline in the quality of its functionaries.

ONCE, publishers could count on literate help, and not need very much of it. They could count on a proofreader, often a retired clergyman, to spot "XCVII" as implausible after "CX." Today's production machinery uses so many half- formed cogs it's doubtful if a "reference book" in the old sense is feasible any longer. We watch the Columbia Encyclopedia get slacker with every revision. (The last time I looked it had turned me into "High Kenner.")

For The Oxford Companion to English Literature to have become, despite glitches, both more readable and more useful: that is the star for Margaret Drabble's jersey, a feather for her cap, a credential for her assault upon Helicon. The best novelist both alive in England and missing from the Companion may well be Margaret Drabble (though, sly lady, she's admitted 250 words on "Drab").