The narrative proceeds to a time fifteen years prior to Marcel's youth at Combray to focus on the beginning of the love affair between Odette and Swann. At that time, Odette belonged to a clique of mediocre, middle-class social climbers who came together each night at the Verdurins' salon. Each night, a trio consisting of a doctor, a painter, and a musician makes the Verdurins believe that they are much more important than they really are. Even though Odette is merely an aspiring courtesan, she is welcome to bring whomever she likes to the Verdurins. Swann is not impressed with Odette at first, finding himself "indifferent" to her appearance; knowing that she likes him, however, makes him begin to pay increasingly more attention to her. When a friend leads Swann to believe that Odette will be harder to seduce than she really is, he begins to fall in love with her.
Swann makes a good impression with the Verdurins because he is an expert socialite who knows how to speak and act as others wish him to. Madame Verdurin is extraordinarily shallow and prone to hysteria, but her taste in music amuses Swann. She asks the musician to play a sonata that Swann had previously attempted, unsuccessfully, to find for the purpose of studying. Swann does not know much about music, and is at first confused by the progression of the sonata. Gradually, however, he feels successive sensations of pleasure, melancholy, passionate longing, and finally, rejuvenation. After explaining to Odette that he had previously heard the sonata and fallen in love with it, he is surprised to learn that the composer's name is Vinteuil. He is positive, though, that it is not the same Vinteuil he knows from Combray.
Swann makes such a good impression on the Verdurins that he is invited to join their salon. He tries as hard as possible to hide his connections to the Prince of Wales and the President of France in order to seem more like the regulars at the Verdurins. However, he rarely stays for dinner, despite Odette's entreaties. In fact, Swann is also seeing a local seamstress and does not really take Odette's advances too seriously. But she eventually conquers him by having the Verdurins' musician play Swann's favorite sonata whenever they are together.
Swann finally visits Odette's house and sympathizes with her desperate attempts to please him. He forgets his cigarette case there, and she writes to him: "If only you had forgotten your heart! I should never have let you have that back." One day, Swann realizes that Odette looks like Jethro's daughter in Botticelli's painting Zipporrah. Associating her with this idealized beauty, Swann falls hopelessly in love with Odette. He searches for her desperately that night in the streets of Paris; he finds her, and they spend the night together.
Proust now turns the narrative away from its autobiographical focus and uses the third person to describe Swann's adventures in this section, appropriately titled "Swann in Love." Swann vacillates between being a hopeless romantic and a heartless womanizer. As the narrator explains, Swann sought only to "spend his time with women that he had already found attractive." He acquires a notorious reputation, especially for seducing the servants and cooks of the families he visits. Proust even hints that the pregnant cook, whom Swann had called "Giotto's Charity," at Marcel's Combray house was actually his mistress. It is further revealing that Marcel's grandfather refuses to recommend Swann to the Verdurins, considering his character unbecoming. Even when he meets Odette, Swann is only impressed with the fact the she will be difficult to seduce. When it becomes clear that Odette likes him, Swann responds to her more out of vanity than out of any actual interest in her.
Proust's pessimistic attitude toward love grows stronger in the last part of the "Combray" section as he explains the psychological traps that ultimately lead Swann toward tragedy. First, Swann's attraction to Odette does not stem from a true interest in her, but rather from the fact that she likes him. More importantly, Swann idealizes Odette and thinks of her as a figure in a Botticelli painting. As a result, his growing love for Odette finds "justification in his own aesthetic culture." Not only does he think of her constantly, but he also reveres her as he revered the great master artists that he studied.
Just as Marcel idealized Gilberte by imagining that her black eyes were really blue, Swann begins to see Odette as Jethro's daughter in Zipporrah and no longer as Odette. His confusion between the real and imagined Odettes culminates in his using a small reproduction of the painting to represent a photograph of Odette. Swann has fallen in love out of vanity, and with a version of Odette—more pleasing than the real one—that he himself has constructed.
Vinteuil's sonata also plays a major role in Swann's falling for Odette. Much as dipping a madeleine in tea allowed Marcel to revisit his days at Combray, the sonata "rejuvenates" Swann and makes him reflect on his youth. Even though the powerful surges of happiness and passion that the sonata evokes in Swann occur long before he meets Odette, its repeated playings at the Verdurins cause Swann to associate these sensations with her presence. As he hungers to hear the sonata, the music becomes the "theme" for Swann and Odette, consequently establishing Odette as a permanent fixture in Swann's thoughts. When Swann later learns that Odette's feelings for him constitute only a flirtatious infatuation, he lets the music carry him back to the "happy" moments when she "loved" him.
Proust counters the tragic tone of this section with a number of humorous interludes, especially during scenes at the Verdurins. His description of Madame Verdurin is not only a witty portrayal of a stereotypical salon leader, but also a scathing attack on bourgeois hypocrisy and ignorance during la belle époque. The Verdurins are a poor match for Swann's refined taste and superior appreciation of the arts; Proust emphasizes this stark contrast in order to demonstrate the lengths to which Swann is willing to go to in order to win Odette. But his failure to recognize that Odette's true character is not so far removed from that of the Verdurins will prove his undoing, as he falls obsessively in love with her just as she begins to tire of him.