Reddit reviews Tonal Harmony

I am going to go against the usual grain and recommend that you avoid guitar related music theory books. They tend to be horribly confusing and poorly represent the mechanics of what is happening. If you go down that road you will probably end up deep in confusing mode nonsense and convoluted ideas that will ultimately hold you back.

Instead, learn to read music, which will bring a good familiarity with note placement on the neck. From there, read a good book on tonal harmony.

Here are my recommended studies:
Modern Method for Guitar

Tonal Harmony