Once, in a moment of admitted light-headedness, I considered the possibility of writing a pair of theory textbooks with literary ambitions of their own. I suspect that the first, Topic of Counterpoint, could have been the first music textbook to sell a million copies, albeit largely under false expectations, while the second, The Rime of the Ancient Harmonizer, might well have been the first harmony primer composed entirely in ballad stanzas.
Fifths, octaves, everywhere,
And all of them parallel!
Fifths of horns and voices crossed,
Learn to hide them well.
The sixth, augmented,
Counts its varieties internationale:
Whether Italian, German, or the French,
Each, over-used, can sound banal.
A dominant seventh chord, with four different tones,
Alone and complete, presents no trouble.
But when it resolves to another dominant, seventh'd,
One of the tones must now be doubled.