Good question, Gary! I guess I am anticipating that I may someday live where I can join in on some sessions and would like to know what is meant when someone yells out what key they are going to play in, BUT, my ear serves me well enough, I can pick it up, intuitively, without really needing to know the technical data, so I guess I don't really have to know. Plus, it's never mattered when I played in the orchestra or piano or violin alone, from written music. Now, if I was going to be fiddling a lot, then I could see a real need for it, because I could relate it to the instrument, but, again, my ear serves well,once i know the piece or hear it a few times. I am not geared to guitars, so would have a tougher time relating it to them in the same way. Hope that makes sense!

Thanks, Mary for the further comments. Despite my lack of this knowledge, I think I've been pretty lucky to have learned the rest of it from my family. Grand ear training, that!

kat