JAMES THURBER was often an irascible and difficult

man, but there is little of that side of his personality

in these Selected Letters. Here we find him for the most part sunny side up--and what a pleasure that is. This is a slender volume, evidently intended to be a representative rather than an inclusive selection of his correspondence, but it contains enough first-rate Thurber to be ranked among his better books.

Indeed, if justice is at work in the world these days, the publication of these letters may initiate a Thurber revival. It is my sense, based on nothing except intuition, that Thurber is not widely read these days--even though his friend, New Yorker colleague and occasional collaborator, E.B. White, remains perhaps the country's most beloved writer. Two decades after his death, Thurber seems to have been relegated to the status of "minor" writer: a humorist of the New Yorker school and the author of a handful of short stories that appear, even now, in anthologies.

But Thurber, as he himself well knew, was far more than that; his literary legacy is larger and more durable. He knew what he was doing, as he told one correspondent:

"Most so-called academic studies of what I write and draw seem to me to overemphasize the 'important' while underestimating the so-called humorous, alias trivial. I simply say to all this that my days, nights and years are an unplanned combination of both elements. If they weren't, I would be all professor or all clown, both of them good things to be, if they are not mutually exclusive. An evening given over completely to serious discussion is as dull as one given over entirely to clowning around. Humor is counter-balance. Laughter need not be cut out of anything, since it improves everything. The power that created the poodle, the platypus and people has an integrated sense of both comedy and tragedy."

Thurber's humor, as these letters at times brilliantly demonstrate, has a timeless quality that should guarantee him a readership far into the future. It is for one thing a deeply American humor, rooted not in the brittle style of The New Yorker but in his own native Ohio, as he noted once in a memorable sentence: "The clocks that strike in my dreams are often the clocks of Columbus." He had in equal measure an appreciation of the ridiculous and the sublime; he once wrote to a woman named Ada Laura Fonda Snell, "Your name is like a waving flag and should never be furled in abbreviation." He loved the Anglo-American language, explored all its labyrinthine passages, and played with it constantly-- yet his humor depended far less on facile wordplay than on deeper, more universal quirks of character and incident.

Like most great humorists, he was his own best target. At times he disguised himself, as in "The Secret Life of Walter Mitty"; at others he made fun of himself indirectly through his family, as in "The Night the Bed Fell." But often he went after himself head on, and never to more hilarious effect than in a letter, written in 1935, to his close friends Herman and Dorothy Miller. At the time Thurber had not yet lost his eyesight, but he had great difficulty driving at night, when "flecks of dust and streaks of bug blood on the windshield look to me often like old admirals in uniform, or crippled apple women, or the front end of barges, and I whirl out of their way, thus going into ditches and fields and up on front lawns." In the letter, Thurber postulated a news story that might follow such an episode:

"Police are striving to unravel the tangle of seven cars and a truck which suddenly took place last night at 9 o'clock where Route 44 is crossed by Harmer's Lane and a wood road leading to the old Beckert estate. Although nobody seems to know exactly what happened, the automobile that the accident seemed to center about was a 1932 Ford V-8 operated by one James Thurberg. Thurberg, who was coming into Winsted at 8 miles an hour, mistook the lights of Harry Freeman's hot-dog stand, at the corner of Harmer's Lane and Route 44, for the headlight of a train. As he told the story later: he swerved out to avoid the oncoming hot-dog stand only to see an aged admiral in full dress uniform riding toward him, out of the old wood road, on a tricycle, which had no headlights. In trying to go between the hot-dog stand and the tricycle, Thurberg somehow or other managed to get his car crosswise of all three roads, resulting in the cracking up of six other cars and the truck. Police have so far found no trace of the aged admiral and his tricycle. The hot-dog stand came to a stop fifteen feet from Thurberg's car."

That paragraph presumably was not written and rewritten, as Thurberg's published pieces were, a dozen times or more; it was dashed off in the heat of correspondence, probably on a busy day when Thurber had much else to do. Yet it has an almost perfect shape and a clear internal logic; and the entire letter, which is quite a bit longer, is a classic of its kind.

In these letters Thurber writes of many things. New York: "A person can admire New York and so on, and all that, but I feel it is absolutely impossible to love the place. One more or less holds on there. It is an achievement to have lived there, not a pleasure to do so." The new age: "Youngsters now bring babble boxes for me to talk into, as we sink further and further into the new Oral Culture. The written word will soon disappear and we'll no longer be able to read good prose like we used to could. This prospect does not gentle my thoughts or tranquil me toward the future." Sinclair Lewis: "The only drunken writer I ever met who said nothing about his own work and praised that of another writer present." Humor: "I write humor the way a surgeon operates, because it is a livelihood, because I have a great urge to do it, because many interesting challenges are set up, and because I have the hope that it may do some good."

Indeed it may. The humor of James Thurber probably had done as much "good" as that of any American writer of the 20th century. Certainly he ranks with those who influenced him, Twain and Lardner in particular, and far above those whom he influenced; in that crowd, only Peter De Vries comes close. Because he was possessed by what he described in My Life and Hard Times as "the damp hand of melancholy," he was all the more keenly aware of the need to bring forth the bright light of laughter. Here he writes, from England, to E.B. White, at a time when White was deep in a dark mood:

"As far as I can make out, what you have is sheep blast. It comes from an admixture of Comment writing and whisk broom catchings. You look up under 'blast' in the dictionary. It is really a flatulent condition of certain sheep, and this is unusual because sheep have almost no diseases. You couldn't give a sheep syphilis, for instance, or vent gleet. Sheep bleat, of course, is common enough, and I have it myself. It causes one to say, 'Hello, George,' to himself in the mirror of a morning. Over here everybody turns Catholic when anything is the matter, and perhaps you should try that. T.S. Eliot turned Catholic and so did Evelyn Waugh and they look fine."

That, for my money, is doing "good." But then so is everything else in this exhilarating, uproarious and wise book; I only wish the editors had given us more.