Musical prose is something I don't think about often, but I do love it when literature has a poetic quality to it. One book like this that pops to mind is The Weight of Ink. There are passages of prose near the end that are just amazing.
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It's not just poetic quality, it's also... Idk, it flows well. Good variety of long and short sentences, vivid, properly placed, and not overused metaphors and strong verbs, etc. I literally feel my muscles relax when I'm reading that type of prose (unless it's a high - action or tense scene that is).