Antoine Roquentin has no need to earn a living. A free man, he devotes himself to the study of a somewhat obscure 18th-century French nobleman and political intriguer, the Marquis de Rollebon. At the outset of the novel, Roquentin has been living for three years in Bouville, where there are records of the Marquis de Rollebon. Before settling in Bouville, Roquentin traveled extensively, particularly in French colonies such as Morocco and Vietnam. In Bouville Roquentin is increasingly transfixed by an experience he calls "the Nausea," in which objects appear unfamiliar and meaningless to him. Even his own hands and face can have this alarming strangeness. Roquentin sees those around him as wrapped up in delusions of meaning, unable to see the dreadful truth of existence the way he does. This perspective on others gives him a certain aloofness. Although he sees himself as unique, the other characters in Nausea are almost his doubles. The Self-Taught Man is also engaged in self-directed study. Anny searches out "perfect moments" just as Roquentin sought out adventures. Even the Marquis de Rollebon was an international man of mystery like Roquentin.
Like Antoine Roquentin, the Self-Taught Man shows up in the reading room at the library every day. He pores over a strange variety of books, consulting volumes on beetles, peat mosses, and a Sanskrit guide to good conduct. His reading is actually guided by an inane principle; he is reading his way through the Bouville library from A to Z. When he finishes, he would like to take a cruise and see the world he has only read about. The Self-Taught Man is a lonely man and a somewhat clingy companion to Roquentin. The defining experience of his life was during World War I. He was taken prisoner by the Germans and was sometimes housed with many other men in a huge, windowless, unlit shed. After the war, he went looking for this experience of intense togetherness, and he finds it in socialism and humanism, a belief that all people are united in their common humanity. Roquentin accuses him of loving an abstract idea of people. In the end, it turns out the Self-Taught Man has other needs for human contact. He is thrown out of the library for making sexual advances to an underage youth.
Anny used to search for what she called "perfect moments," which were charged or heightened situations. She thought being an actress would be a way to bring these perfect moments to the stage. But she has become disillusioned with acting and with the search for perfect moments. By the time she meets with Antoine Roquentin again, six years after their breakup, she is pessimistic about life. She feels she has "outlived herself." She is still alive, but inside she's dead.