The aunt, who keeps a spotless bourgeois house, is attracted to Harry Haller, the new lodger who rents her attic, but her nephew’s suspicions are aroused when the lodger asks them not to report his domicile to the police. Haller explains that he has a repugnance for official contacts. His room is always in disorder; cigar ends and ashes, wine and brandy, pictures and books litter the apartment.

Haller is about fifty years old, sometimes in poor health and addicted to painkillers. He arises very late and becomes active only at night. He is invariably polite but remote. Once the nephew finds him sitting on the stairs near a landing. Haller explains that the landing, which smells of wax and turpentine and is decorated with washed plants, seems to him the epitome of bourgeois order. Occasionally a pretty girl comes to see Haller for brief visits, but her final visit ends in a bitter quarrel.

One day, Haller disappears, after meticulously paying his accounts. He leaves behind a manuscript, written during his stay, which tells the story of a steppenwolf. The nephew, sure that Haller is not dead, makes the account public.

Haller suffered a series of blows. His wife became mad and chased him from the house. His profession was closed to him. Living a solitary life, he became a divided personality, one part of him a neat, calm bourgeois, the other, a wolf from the steppes. When he acted politely and genteelly, the world mocked his respectability. When he snarled and withdrew from society, he shocked his bourgeois self. He seemed to be a true steppenwolf.

On a solitary night ramble, he thought he saw an electric sign over a Gothic door in an old wall. The words, which he could barely discern, told of a magic show only for madmen. A little later, he saw a peddler with a similar sign. From a hawker he bought a treatise on the steppenwolf and read it avidly.

The treatise explained the popular concept of a steppenwolf, a creature that is half wolf and half human being as a result of mischance or spell. This was an oversimplified concept, however, for everyone is actually composed not of two but of many selves. The great bulk of the populace is held to one self through the rigid patterns of the sheeplike bourgeoisie; only a few individuals, ostensibly complying, are not really part of the pattern. They act like the lone wolf and are the leaders in all fields. Meditating on this philosophy, Haller understood his own nature a little more clearly, but it was difficult to think of himself as containing many selves.

An old acquaintance, a professor, met him and insisted on inviting him to dinner. The occasion was not a happy one. The professor and his wife were naïvely jingoistic and approved a vicious newspaper attack on a writer who advanced the opinion that perhaps the Germans shared the guilt for World War I. The professor did not realize that the writer was his guest. Haller, for his part, ridiculed a pompous painting of Johann Wolfgang von Goethe that turned out to be greatly prized by the professor’s wife.

Feeling the wolf in him gain ascendancy, Haller dropped in at the Black Eagle Tavern, where merriment reigned. At the bar, he encountered a young girl whom he thought sympathetic. He told her his long tale of woe, including the professor’s dinner and his mad wife, Erica, whom he saw only every few months and with whom he quarreled. The girl, who refused to give her name, good-naturedly ridiculed his preoccupation with Wolfgang Amadeus Mozart and Indian myths when he did not even know how to dance. She seemed almost motherly in her concern for him; when he confessed he was afraid to go back to his lodging, she sent him upstairs to sleep. Before they parted, Haller made a dinner date with her.

At their next meeting, the girl, who said that her name was Hermine, set out to change Haller. She would help him for friendship’s sake, so that in the end Haller would love her enough to kill her. Haller himself had thought of death; in fact, he was seriously contemplating committing suicide on his fiftieth birthday. Perhaps that was why he did not think Hermine’s plan strange.

Hermine began her campaign. First she took him shopping for a gramophone, whereupon he took dancing lessons in his cluttered room. Although he was stiff, he learned the steps of the foxtrot. Then she took him to a tavern to dance. At her urging, he asked the most beautiful girl there, Maria, to be his partner. To his amazement, she accepted, and they danced well together. Hermine complimented him on his progress.

Late one night, as Haller returned quietly to his bedroom, he found Maria in his bed. Thinking he was too old for her, Haller hesitated; Maria was so sympathetic, however, that he lost his reluctance. He met Maria frequently in another room he rented nearby. Haller was grateful to Hermine, who arranged it all. She kept track of his progress in love. After some time Haller realized that only through a lesbian relation could Hermine have known Maria’s technique so well.

Another new acquaintance was Pablo, a gentle, accommodating saxophonist. He agreed readily with Haller’s criticisms of modern jazz and with his preference for Mozart. Nevertheless, Pablo felt that music was not something to criticize; it was something for listeners and dancers to enjoy. Part of Pablo’s great popularity came from his ability to provide drugs for jaded profligates. One night, Pablo invited Haller and Maria to his room and proposed a love episode for three. Haller refused abruptly, but Maria would have liked to accept.

On several occasions, Hermine hinted that she was more unhappy than Haller. He was learning other sides of life, but she knew only a life of pleasure and the senses. She was hoping that Haller would come to love her, because at the coming masquerade ball she would give her last command.

At the ball, Hermine was dressed as a man, reminding Haller of his friend Hermann. They danced with many different women. When Hermine finally changed into women’s clothes, Haller knew that he loved her. After the ball, Pablo took them up to his Magic Theater. In a hall of mirrors, Haller saw his many selves; in the various booths, he lived his many lives. In one booth, he killed automobile drivers recklessly. In another, he met all the girls he had ever loved. Toward the end, he was Mozart, a laughing, reckless Mozart who played Handel on a radio. The whirling came to an end. In the last booth, he saw Hermine and Pablo naked on a rug. They were asleep, sated with love. Haller stabbed Hermine. In the court, Mozart was his friend and comforted him when the judges sentenced him to eternal life; he was to be laughed out of court. Mozart turned into Pablo, who picked up Hermine’s body, shrank it to figurine size, and put it in his pocket.