Animorphs Book 7: The Stranger by K. A. Applegate

Rachel is offered a way out of her current life, and the Animorphs are offered a way out of everything when they meet the Ellimist. The nightmares and secrecy build a miasma of isolation that is gradually permeating the series.

This was the first series I read that dealt with divorce from the perspective of one of the children who was affected. I appreciate that it's part of Rachel's life without being the point of the book, let alone the point of the series. It affects her, but we mostly see it when she's the narrator instead of it being treated like the main trauma. It matters without sucking all the air out of the narrative.

I'm also really appreciating how much changes as the book moves on, I know 62 books seems like a lot, but they really have to handle a lot of moving pieces to get where I know the series ends up going.