This uneven book by John Casey, author of the well-received novel "An American Romance," contains three excellent short stories and a so-so novella. The best of the stories, "A More Complete Cross-Section," concerns an assault on the narrator, a privileged intellectual, by the soldiers over whom he has nominal command. One morning, annoyed at his easy capability and aloof scrutnizing - he welcomed militaty service, he tells us, "as an opportunity to see a more complete cross-section of my fellow man" - the soldiers snarl him in a blanket and jab him with broom handles. He gets away with only a few bruises, but his detachment is gone. "I had to scuttle away," he says, "because they tore apart the pleasant distance at which I lived." Since he is sure he has been fair with them, he concludes that they jumped him to see what he would do. "I think their . . . outburst was almost more curiosity than resentment," he explains. "They probably wanted to see, too."

If one asks more from a story than lively incidents, vivid characters and a stimulating payoff, this one has it. Shortly before his hazing, the narrator is assigned to KP for publicly squelching a superior officer. In a remarkable passage., Casey describes the peace that steals over the narrator as he peels potatoes. It is a bit of phenomenological analysis as subtle as a meditation by Merleau-Ponty, and it is worth quoting in full.

"Calm is most regularly induced to enter the physical world by a series of ornamentations; it doesn't matter whether it is nature or oneself that executes them, so long as there is a strtch of repetitive exertion from a single source. Waves befor the wind. The footfalls of a runner spinning the world beneath him. Paddle weirls in the wake of a canoe. Or curlicues of potato skin, as unbroken as the phrases sliding out from under the bowing hand of a cellist.

"These repetitions are felt by our bodies, the deft, hardworking, and unsuspecting bundles in which we are enmeshed. Unsuspecting because it is by their effors, the spasms of nerves and muscles that we command into rhythm, that they are calmed. And the calm rends them - plucks their fivers apart so that the spirtit escapes to a dominant position. That is contentment, I suppose, and most people happen on it only by chance."

The title story is nearly as good and stands comparison with the law stories in Louis Auchincloss's "Powers of Attorney." Charlie, the narrator, a workaholic associate in a New York law firm, is befriended by Mr. Pelham, a soliloquizing elderly partner. For all his garrulity, Mr. Pelham has enough intellect and flair to bring off a paean to the tax code: "I mean, in one sense the tax structure is art - a subsuming of the infinite muddle of human activity under a single rubric, as though it has a single purpose and could be ordered by a mind hewing to the line of single vision. Everything that everyone is doing in this part of town has tax consequence. Do you ever feel the impact of that?'"

Introduced to Mr. Pelham's friends, Charlie takes up with a woman 20 years his senior. After a few pleasant weeks of seeing him, she travels to France, where, suddenly, she marries. Charlie is hurt but comes to see that the greater loss is Mr. Pelham's; The woman is one of his dearest friends. Charlie assumes a certain duty toward the older man: "I should deal with this man, help keep him from sonething - growing coldness, slowign down." Through his knowing Mr. Pelham, Chrlie's singleminded life has become augmented by "luxuries and encumbrances."

By now a pattern is emerging from Casey's stories. They center on the initiation of a gifted and cosseted young man into rougher, more compromising circles. This, of course, is a hoary theme, but Casey refreshes it with his attention to nuance.

"Mandarins in a Father Field" varies the theme only a little. A Russioan diplomat forces a young Washington bureaucrat to acknowledge the limits of his public-policy vision and ambitions. Among other attractions, it serves up the comedy of international friendships.

Unfortunately the novella, "Connaissance des Art," comports with the priggishness of its title. It follows the narrator, a graduate student and teaching assistant in English, between his post at an Iowa university and his vacations in Manhattan and watches him fall in love with a callow but vibrant student. It has a fine set-piece - a runaway ballon ride over the fields of Iowa - but Casey fails to draw together the far-flung elements of his narration. Yet the novella is among the most intractable of literary forms, and Casey's way with the short story is enough reason for getting his new book.