I first took music lessons in 1966 at Wright's Music on Dupont St., Flint, MI, when I was just 9 yrs old. I studied sight reading and theory, and during that time, one of my teachers loaned me a book called "4,400 Guitar Chords". I still have the book, because he moved on, and I was unable to return it. My approach to chords takes the mystery away, along with the intimidation of 4,400 chords to memorize; there really aren't that many chords, they are all just repetitions of the same thing, in different places.
If you can learn one simple three-note chord, you can use Chord-Chemistry to alter it and make many other chords. Think of these formulae as 'recipes' that describe the ingredients needed. For example, if you have banana pudding and you add strawberries, you have created strawberry-banana pudding. Add the sixth note of a C-scale to a simple C Chord, and you have created a 'C6' chord. For all the recipes to create many 'types' of chords, see the Chord Chemistry chart.
I have lots more to say about chords, so watch this page for subsequent lessons and updates.