The popularity of the regional tunebook outside of the core area can be attributed to a design that has been optimized for sight-singing: "visually attractive, the songs are easy to read ... and the book feels good in your hand," Another reason is that shape note singers love minor-key songs; and the "Shenandoah Harmony" satisfies this peculiarity more than any other publication in current use: 52% of the tunes being minor.