EVERYTHING THIS STRANGE

IS REAL

FORTY STORIES By Donald Barthelme. Illustrated. 256 pp. New York: G. P. Putnam's Sons. $17.95.

In one of the best, most typical Donald Barthelme stories, a show is staged in an abandoned palazzo. Among descriptions of performing grave robbers, tax evaders and trapeze artists, one sentence jumps out like a crucial clue to this volume of ''Forty Stories.'' ''Some things appear to be wonders in the beginning, but when you become familiar with them, are not wonderful at all,'' worries the narrator of ''The Flight of Pigeons From the Palace.'' Versions of that fear may haunt the reader of this selection from nearly 20 years as well: How will Mr. Barthelme's iconoclastic stories hold up after he has shattered the icons of character and plot? Will reading these now-familiar, fantastic tales resemble an adult's visit to the circus, where the magician's tricks are far less wondrous than they once seemed?

The comforting rediscovery to be found in ''Forty Stories'' is that Mr. Barthelme was always more than a first-rate circus performer. Even in stories from the 1970's (more than half of this collection), he is not content to stand on his head so we can see the world differently. His funny, ludicrous tales follow the emotional logic of a dream, and as he tells them no slice-of-life could seem more substantial. St. Anthony moves to a middle-class suburb; a genius uses ''a green Sears toolbox'' as a briefcase. In daylight, on the printed page, these cockeyed scenarios evoke nervous laughter, for dreams too often reveal the distilled, uncensored truth. Gossips say St. Anthony put his hand on a young woman's knee. The genius ''is a drunk.''

In creating these strange conjunctions, Mr. Barthelme does not play nonsense games, and does not force his imagination to mold neat little symbols. His stories have substance because he locates his characters - from unnamed narrators, to a generic ''playwright'' to Paul Klee and Goethe - in the precise place where the weight of history intrudes on the present, where desire meets imagination. That is the spot where they live, and often it is a place Mr. Barthelme must invent. He is especially fond of made-up museums.

In ''The Educational Experience,'' students are guided through exhibits that include a bird's lung and a gas turbine. The teacher-narrator describes the tour: ''The students looked at each other with secret smiles. Rotten of them to conceal their feelings . . . The invitation to indulge in emotion at the expense of rational analysis already constitutes a political act, as per our phoncon of 11/9/75. We came to a booth where the lessons of 1914 were taught. There were some wild strawberries there, in the pool of blood, and someone was playing the piano, softly, in the pool of blood, and the Fisher King was fishing, hopelessly, in the pool of blood. The pool is a popular meeting place for younger people but we aren't younger anymore so we hurried on.'' As the narrator's brusqueness swiftly gives way to lyricism, we are pulled toward the forbidden, politicized emotion.

''At the Tolstoy Museum,'' certainly among Mr. Barthelme's finest stories, is a comic and touching romp that starts by emphasizing the sentimental pull of the past and ends by stating the confusion of the present. ''At the Tolstoy Museum we sat and wept. Paper streamers came out of our eyes,'' the narrator begins. ''The guards at the Tolstoy Museum carry buckets in which there are stacks of clean white pocket handkerchiefs. . . . Even the bare title of a Tolstoy work, with its burden of love, can induce weeping.'' Mr. Barthelme succesfully weaves illustrations into the story; we can see this museum. Identical portraits of Tolstoy look out at us from facing pages, but in one of them a tiny figure of Napolean stares up at the giant face. A woman faints in a man's arms in an architectural drawing of ''The Anna-Vronsky Pavilion.'' Still, the ''burden of love'' Tolstoy's words carry is a thorny problem, and at the story's end the narrator isn't sure whether he's glad Tolstoy existed or not.

Mr. Barthelme's most resonant stories end with such unresolved questions, or with images that will not allow themselves to be explained. ''Visitors'' is a rather conventional work about a man named Bishop. He stays up all night looking after his daughter, who is ill, and thinking about a failed love affair. Suddenly, the story ends with an image that distills questions about how we love and get on with life. From his window, Bishop often sees the ''two old ladies'' in the apartment behind his ''having breakfast by candlelight. He can never figure out whether they are terminally romantic or whether, rather, they're trying to save electricity.'' Who are these women? What are they to one another, and how do they live? They are haunting figures precisely because Mr. Barthelme will not say; but like his strongest characters they live in a moment of heightened reality, containing the extremes of endless romance and penny-pinching practicality (both of which are probably terminal).

The creeping realism in ''Visitors'' marks it as a work from the 80's. It is, in fact, one of seven stories taken from Mr. Barthelme's 1983 volume, ''Overnight to Many Distant Cities.'' Nine more of the ''Forty Stories'' have not appeared in collections. Most of these fairly recent works are of a piece with Mr. Barthelme's 1986 novel, ''Paradise,'' which anchors it's hero's sexual fantasies in the fairly mundane reality of his family life and work. ''Construction'' is a deft meditation by a businessman confused about ''the long-range plan,'' and the mystery of a colleague named Helen; next to Mr. Barthelme at his ambiguous best, though, the story feels too pat when the narrator comes out and asks, ''Why am I doing this?'' The most memorable recent work is still the least realistic. ''Bluebeard,'' for example, is a gleeful retelling of the legend. Set in 1910, the story piles reversal on reversal until the tormented wife enters Bluebeard's secret chamber and faints ''with rage and disappointment'' at the silly vision - it involves Coco Chanel - only Donald Barthelme could have imagined.

Collections such as ''Forty Stories'' are, of course, uneven by nature. Many of the best Barthelme works were included in ''Sixty Stories'' in 1981. And a few tales in the new volume show Mr. Barthelme at his most glib. ''Porcupines at the University'' is a mere cartoon, dated by its references to the Sonny and Cher show. By contrast, though, it reveals how very well almost all these stories have aged.

''Forty Stories'' also suggests why Mr. Barthelme cannot be easily classified. His playful fiction does not deeply resemble the extravagant work of John Barth or Robert Coover; at his most realistic, he's a far cry from John Updike; and he is much more than the fractured flip side of minimalism. Donald Barthelme is the author who discovers small, bizarre conjunctions that make enormous sense and offers them in a voice that remains uniquely rewarding and often sounds ageless. THERE GOES COLBY AGAIN

Some of us had been threatening our friend Colby for a long time, because of the way he had been behaving. And now he'd gone too far, so we decided to hang him. Colby argued that just because he'd gone too far (he did not deny that he had gone too far) did not mean that he should be subjected to hanging. Going too far, he said, was something everybody did sometimes. We didn't pay much attention to this argument. We asked him what sort of music he would like played at the hanging. . . . Colby said he'd always been fond of Ives's Fourth Symphony. Howard said that this was a ''delaying tactic'' and that everybody knew that the Ives was almost impossible to perform and would involve weeks of rehearsal, and that the size of the orchestra and chorus would put us way over the music budget. ''Be reasonable,'' he said to Colby. Colby said he'd try to think of something a little less exacting.

From ''Forty Stories.''

THE NEW YORK TIMES