Deep in the realm of Marcel’s youth, his extended family, and the people of the town of Combray, where one person not knowing another is shocking. It’s probably not a common association, but I think of that dusty, windswept Texas town in the movie of The Last Picture Show and how every possible interpersonal combination has to be explored by the inhabitants (and the author) just to distract themselves from how desolate the whole place is.
This isn’t to say that Combray works in the same way, but the centrality of Combray and its removal from Paris, to the point where it seems out of time and most larger context, acts as the main limiter of what the youth Marcel is exposed to in this section. In the preface the world was the size of his bedroom, which he wanted his mother to re-enter; now it’s the size of an idyllic small town.
It’s not just him. The attraction he feels to the plain, unnoteworthy church of Combray is shared by his grandmother. The implication: objects are granted aesthetic significance by those people who project their memories onto it.
A few character studies are striking:
The fall of M. Legrandin: Legrandin is an effete snob who, initially respected by Marcel’s family, falls from favor after Marcel induces his family to tie him in knots over the fact that he’s not quite as high and mighty as he claims to be. (The actual circumstances are too twisty to summarize easily.) It only takes a single gesture on his behalf to convince Marcel that his act isn’t justified.
M. Vinteuil and his daughter: Vinteuil has no idea how rotten and amoral his daughter is, and by the time she spits on his picture (a terrible act by the standards at work here), he’s already dead. He’s much gossipped about, but he himself never realizes.
Francoise and Leonie: Leonie is Marcel’s aunt, Francoise her cook. Leonie hasn’t been doing well and has thrown all sorts of paranoid accusations at Francoise, who’s weathered them as best as possible. Yet after Leonie dies, the family realizes “the sort of terror in which Francoise had lived of my aunt’s harsh words, her suspicions and her anger, had developed in her a feeling which we had mistaken for hatred and which was really veneration and love.”
These miniatures (none take more than a couple pages to play out) all deal with conflicting representations of other people (or of one’s self). While one interpretation is designated “correct” each time, the revelation is always a tad uncertain, since it’s simply a revision of an earlier account, not a true reckoning.
In turn, it makes me wonder about the revelation of Mme de Guermantes, the local noble whom Marcel imagines so vividly without having met that, when he finally sees her, the sight doesn’t permit him to reject his fixed idea of her, but instead amplifies it. Again, it’s more of a revision than a true correction.
As, to some extent, with books. The Bergotte passage, about Marcel’s infatuation with and worship of an author, was the first that made me realize that there was a decent chance I would complete the entirety of ROTP, that no matter how many dull stories of aristocratic intrigue or explorations of uninteresting minutiae, there was enough depth to the reflection at times to keep me going through the dry patches, which I’m steeling myself for.
(Compared to Robert Musil’s The Man Without Qualities, it was a more difficult assessment. There are large dry passages in MWQ, but the payoffs are so self-contained and so dazzling in their ideological genius that the promise of continued, new treasures made it easy to keep going. Add to that the constant tension of World War I looming over all the characters and the narrative, promising to destroy all their dreams and high ideals, and the irony grants resonance to each bit of politics or theory. There is much more of a cumulative effect in Proust, with a fair amount of (so far) deadwood being thrown into the mix.)
He reads Bergotte, who’s an imagined author who deals in aethetic lyricism and symbolic images (he sounds a bit German). One passage makes a particular impression on him:

I now had the impression of being confronted not by a particular passage in one of Bergotte’s works, tracing a purely bi-dimensional figure upon the surface of my mind, but rather by the “ideal passage” of Bergotte, common to every one of his books, to which all the earlier, similar passages, now becoming merged in it, had added a kind of density and volume by which my own understanding seemed to be enlarged. (102)

And that’s why I kept reading too. It’s a better description of a reader’s revelation than anything I’ve gotten from Northrop Frye or Leavis.
This sort of experienced synecdoche (an approximate term here) returns later in Swann’s apprehension of a piece of music, so I’ll get back to it.
And finally, something that jumps off the page, Marcel’s view of women prepubescent vs. post-pubescent. He speaks of “that period of life when one has not yet separated the fact of this sensual pleasure from the various women in whose company one has tasted it, when one has not yet reduced it to a general idea which makes one regard them thenceforward as the interchangeable instruments of a pleasure that is always the same.” I don’t know if this makes him a sex-hating anti-Puritan aesthete or someone simply obsessed with multiplicities of experience.
More likely than either, it gets back to his obsession with the child’s immediate experience of sensations with less than the full complement of an adult’s prejudices, sex being one of the most dominant.