What concepts in physics were used before Einstein formulated his theory?

I wish I could tell you that I learned a lot from your article ~ and it would be true if I could ever truly understand what the heck Einstein was talking about!

I accept and appreciate the fact that E=mc2 is as important as you say it is, and from what little I do understand about the theory, I agree it should be preserved.  I just wish that I personally got it.