Linden, thank you SO much for this recommendation; I fell hard for Meg Howrey's The Cranes Dance. I'm going to run out and get her other books, but I think this one will be hard to beat, because it's full of details from the world of professional ballet. Insider bits make any story that much more fascinating.
I was completely won over in the first chapter, when the narrator, Kate Crane, takes you through a production of Swan Lake. Now, this is the one ballet I've ever seen performed (no, I've never even seen The Nutcracker), and I've read a novelization of the story, and I still barely know what happens in it. Kate has a wonderfully wry voice as she explains, for the vast majority of the world that does not follow ballet, all the comings and goings, and the long dancy bits.
Kate's wry voice is really the core of this story. Ballet, as I think most people know by now, is hard, physically taxing work in a fiercely competitive environment that is judged by exacting standards. Kate is near the top of this world, in a very comfortable place within it, but it's consumed her whole life, and her sister's, and she's split between wondering if it's worth it and wondering what that even means.
The competition here is not made melodramatic--there's no catfighting or backstabbing. But there are only so many excellent roles to go around, and there are more gifted dancers who have given their whole lives for this goal than there are places. Everyone is good, but everyone wants things that not everyone can have.
Kate is a powerful dancer, but her sister Gwen is in a class by herself, Gwen's emotional struggles, her mental health, and her break from ballet are pivotal to the story, though Gwen herself is mostly not present. Kate is a sister without a sister, and it leaves her adrift.
I'm not describing this well, but let me say that Kate's day to day life, the sharp, witty view she brings to everything in her life, even as she's questioning it all, is really the driving force of the story. Kate has everything she's worked for, and somehow it feels both right and wrong to her at the same time. This dissonance, and her blunt, smart, wry observations about it, make this the most readable book I've read in a long time.