Book: Music Theory for the 21st-Century Classroom

by Robert Hutchinson

https://musictheory.pugetsound.edu/ link takes you to the homeworks/assignments and everything else for a self-study/auto-didact to follow along. Neat!

Am I the only one who thinks that the classic music notation is 3x harder to learn than the basic music theory (without the rules of notation)?

I think that you can learn music theory (to play an instrument or to compose music e.g. in a "piano roll tool" / MIDI editor) much faster if you skip the classic notation. And I think that it is even better to learn the notation AFTER you understand the music theory.

I even made my own guide to music :D https://www.jampea.com/learn