Hi. I just wanted to know about the theory of Key signatures(if there is any). I mean, I know how most keys are constructed (R,3,5), but I want to know, are keys relevant to the important notes of a scale? For example, take the Aminor scale. It has a flatted 3rd, 6th and 7th. Because these notes differentiate this scale from the Major scale, are these therefore the notes that dictate the key? Or is it all just as simple as R,3,5? BTW, I'm not asking for a full explanation, a website link will be fine. However, if you feel the need to teach, go right ahead!