THE INNER MAN by Martin Walser, translated by Lisa Vennewitz (Holt, Rinehart & Winston: $15.95; 276 pp.)

Chauffeur Xaver Zurn, driving his wealthy employer across southern Germany in a pale-green Mercedes, needs to relieve himself. But it is more than that. There are global aspects, universal dimensions to his abdominal agony.

History furnishes a lesson for his retentive struggle. (“Xaver had read descriptions of battles during the Peasants’ War. Whenever the horde of peasants yielded a mere fraction, (it) would be swept away in headlong flight.”) Religion is there. (“Think of Jesus Christ,” he reflects, speeding towards Stuttgart and its sanitary facilities. “This afternoon you will be granted deliverance.”)

And of course, it is a state matter. (“It always infuriated Xaver when some industry-oriented group lashed out on TV against the deficit of the Federal Railway. If only because of its public and almost always spotless toilets, he was happy to concede however many billions of marks were required.”)

Xaver, compulsive and touchy, is a model of outward order and, inwardly, a raging hell. At one level, he is Martin Walser’s comically inventive caricature of modern Germany. But he is more. He is imaginative and a yearner. If his little-man megalomania makes him alternatively absurd and sinister, sometimes verging on madness, there is humanity to him. Humanity reduced by out-of-scale circumstances; a Gulliver exiled from birth for life in Brobdingnag.

Xaver has floated modestly up on the tide of postwar German prosperity; he lives with his wife and two daughters in a house inherited from farmer parents. There is an orchard attached and a forest adjoining. He is well paid and well treated by Gleitze, a successful industrialist whose consuming avocation is traveling around to performances of Mozart operas; he plans to write a book about them. So far, so good. Xaver loves his wife, Agnes, and his daughters, and the farmhouse and the woods. He serves Gleitze with painful devotion and punctiliousness. He is pleased with everything. And everything torments him. Each tiny detail of his life pumps him up to fury. He goes into a restaurant and flies into an interior rage because of the way somebody looks or dresses or speaks to a waitress. A painting of a country scene infuriates him because of the angle at which the oxen are moving.

He swells alternately with euphoria and anger. Sitting in the front of the car, he imagines himself joining in the conversation of his employer and guests in back. He too has jokes to tell, ideas about Mozart, interesting anecdotes about his family and his experiences. The next moment, he is burning with resentment because he feels all but invisible to his passengers.

When Gleitze arranges for him to have a series of expensive medical tests for his nervous indigestion, he is at first gratified. He is being treated importantly, he thinks. Gradually he grows angrier and angrier. What business is it of Gleitze to have his, Xaver’s, insides examined? Added to the indignity of proctoscopies and barium enemas is his conviction that it is a form of management espionage. Gleitze is not humanly concerned, he comes to believe, but is simply sending his chauffeur to be checked as he would his car.

When bitterness overcomes him, he goes out and buys a knife. He has six so far, and by the middle of the book, we feel that Xaver is a mass murder waiting to happen. But Walser’s purposes are larger and more complex.

Xaver’s flayed skin, his conviction that every bit of data he takes in is a signal, usually threatening, directed personally toward him, is a mark of monstrosity. The monstrosity is not his, though, but society’s. It is like the dwarf condition of the protagonist in “The Tin Drum.” Walser’s point is that the dehumanization of modern life, and particularly modern German life, distorts the individual.

An unremarkable point, perhaps, and Walser’s portrait of the German variants on greed, bad taste and the depredations of authoritarian technology is not new, though it possesses a fresh and aching accuracy. What makes “The Inner Man” unforgettable is the depiction of Xaver and his family. You denounce a society best by showing a good man turned desperate or mad, and the better you show the goodness, the harsher the denunciation.

And as we follow Xaver along the highways, in the hospital, at home with his family, we gradually realize that under the absurdity and the dangerousness, he is Walser’s Everyman, possessing innocence and even nobility. But he is cut off from his natural bearings. Those things that he feels ought to have value--his job, his employer’s apparent benevolence, the order and prosperity of German life, his family--all seem contaminated. Hence his manic pursuit of signals.

He dwells on the past: on a brother killed in the war, on another brother who lost the German rifle finals by scoring a perfect bull’s-eye on an opponent’s target, and on the Peasant Revolt in the 16th Century, lost when the insurgents trusted the promises of the nobility and laid down their arms despite their own superiority.

He repeatedly recounts these things. But he tells them in a particular way; as if until the very end, the stories might end happily, as if defeat were not inevitable but an accident of war. “Without a war, a Zurn life turns out well today, remember that,” he dins into his daughters. “He was always afraid they would suddenly confront him with reproaches at having brought them into the world.”

Xaver is a derailed optimist, believing that what a person does makes a difference. So is his devoted wife, Agnes, who works industriously by day and dreams at night that disgraced public figures such as Nixon and Willi Brandt come creeping to her through the currant bushes to seek comfort and consolation. The Zurn faith is not absurd; the world makes it absurd. The recurring motif of the Peasant Rebellion is a key to Walser’s intention in this ingenious, funny and finally very moving book. The docility of the modern German masses, he suggests, is also a capitulation for fraudulent promises and rewards. Xaver’s perquisites as Gleitze’s chauffeur--the splendid car, his expense account, his proximity to the rich and cultivated--are just such a fake. And he finally finds release from his rage when he is released from his mock glory. He is demoted, at the book’s end, to an ordinary job working in Gleitze’s warehouse. For the first time in years, he can make peaceable love to Agnes.