ELI5: Explain Like I'm 5

Treatise on Harmony

A treatise on harmony is like a big book that teaches you how to make different musical sounds happen at the same time and sound good together.

It's kind of like making a cake. First, you need to know which ingredients you need to use and how much of each one to add. In harmony, these "ingredients" are musical notes.

Then you need to know how to mix those ingredients together in the right way. In harmony, this is called "voicing" and it means figuring out which notes should be high or low and in what order they should be played or sung.

Finally, you need to know when to put the cake in the oven and for how long. In harmony, this is called "timing" and it means knowing when it's best to change to a different set of notes or when to add a special effect like a pause or a crescendo.

So, a treatise on harmony is like a super helpful cookbook that tells you everything you need to know to bake a really tasty musical cake!