Here's an oldie, but goodie for Penguin. I of course tried a couple directions showing tons of instruments (that was fun sourcing), but I was quite happy that the final featured just the conductor's hands. Simple, but effective. I also used those "hot" colors I like. Georgia first mentioned that term and I realize I use these colors a lot...if only they would get approved more often.
Look at that spine...doesn't every book cover designer love a spine they can really work with? Ah, ornaments.