I love how everything feels like a memory, a long cherished memory. This is such a beautiful book.
As to what it’s “about”, I would say it is about longing and trying to belong. Meaulnes knows nobody at the party, is an imposter, he lives as a boarder with no family, and is dreamy and lonely. We’ve all felt like him from time to time.
And did that boy kill himself? Was that his carriage, his gun?