Editor's choice; The Essays, Articles, and Reviews of Evelyn Waugh, edited by Donat Gallagher. Boston, Toronto: Little, Brown. 662pp. $40.

Thomas D'Evelyn is the Monitor's book editor. The appearance of this book is a ''literary event,'' but it is a sobering one. This is the last Waugh we are likely to get. Books by Waugh have been coming since l926; and readers of National Review and The Saturday Evening Post, to mention only American periodicals, were reading new pieces by Waugh in the ' 60s. Gallagher has here collected most of the ephemera as yet uncollected.

Ephemeral they are not. We may have forgotten what inspired them, but these pieces, so closely related to what was going on every day, retain their freshness and significance. A review of a forgotten novel by Robert Byron is entitled ''Civilization and Culture.'' It is only two pages long. Two pages by Waugh can indeed say something about civilization and culture worth reading and rereading.

Waugh's writing has true gravitas - and that's sobering in an age dominated by New York fast talk. It is also sobering to see how hard Evelyn Waugh worked. As he said of Dickens, Waugh ''worked and worked and worked.'' And he almost always worked to effect. Never a mere stylist, he wished to say something, and knew how to say it lucidly, elegantly, memorably.

Unlike Logan Pearsall Smith, an American who interested him, Waugh wrote because he had to write. He wrote, that is, for money. Of course he also had to write in the other, psychological sense, and in this way I suppose he is like the great master of pure style.

Both Waugh and Smith hated shoddy prose and shoddy thinking.

But Waugh's subjects are those of the journalist and man of the world, not of the aesthete. He customarily wrote about things he knew firsthand. In novels, travel writing, and dispatches, he trained his eye on the historical present and his judgment on the slippery world of fashion and politics where real gold can seem like fool's gold. He went to Hollywood; he compared Santa Monica with Alexandria. He came back and wrote about it (April 30, l947, Daily Telegraph and Morning Post): ''It may seem both presumptuous and unkind to return from six weeks' generous entertainment abroad and at once sit down and criticize one's host. In the case of Hollywood it is neither.''

Reviewing a book by Douglas Woodruff, editor of The Tablet (for which Waugh wrote, and in which he was attacked), Waugh writes of Woodruff as he might of himself, but without irony or bitterness. ''He sees the present in a vast perspective and yet maintains an interest in it, seeing modern follies in their most absurd light and yet remaining genial and hopeful.''

Read that again: It is a cameo of Caritas, intelligent charity. Waugh measured himself by that standard. As a writer, he moved in civilized society (''That world still exists and is the proper milieu of the writer,'' Waugh wrote in l956); as a man, he faced temptations to anger and dejection every day. Absurdity sometimes overwhelmed geniality. But in April of l947 he wrote, ''The artist's only service to the disintegrated society of today is to create little independent systems of order of his own. I foresee in the dark age opening that the scribes may play the part of the monks after the first barbarian victories. They were not satirists.''

Waugh was a satirist, and more. He was also an artist: he was an artist who sometimes wrote satire. It is not so much what he said as what he did that matters. What he did was leave us with prose ''structures'' and ''systems'' (his words) that provide unique sanctuary for the spirit. Here's to Evelyn Waugh.