Catalin Matía would smile whenever someone described great music as divine. To him, that was nonsense. Great music is all about weakness, uncertainty, mortality — what does Heaven know of these?
Among other things, this book is a love letter to music in general and the violin in particular. The instrument is a refuge from the world; an outlet for feelings that cannot otherwise be expressed; an elegant and venerated object; a means to produce transcendent beauty. For at least one character in this book, music is so sacred that she would sell her soul for it. While that's obviously over-the-top, I share this general reverence for music. There are times listening to a song when I'll be overcome with sheer awe that something so perfect and wonderful could exist. Few other things in life ever manage to be as sublime. Another theme of the book is the search for meaning in the face of death, and I think it's quite fitting to involve music in that conversation.
Bartók's Sonata for Solo Violin plays a key role in the story, and I listened to it for the first time after I finished reading. It's... unpleasant. But Aoki had not led me to expect otherwise. The passage where a character playing the piece reflects on how each movement connects to her own emotions and life experiences is one of my favorite parts of the novel.
Aoki does a great job of using a fundamentally silly setting - at one point a literal demon chases a purple humanoid alien donut-shop owner into space - to tell an emotionally serious story. I'm a fan of this sort of unapologetic mixing of absurdity and depth.