theater - the basics

I have come to terms with what I believe is a fundamental statement - I have no idea about my theatrical tradition. I mean, I have read books and I believe I know who did what.... but I do not understand the underlying priniciples behind doing theater.
I want to go back, and understand the need, and the basic forms.
These thoughts came to me while I was helping Barry organize his prints. I look at them, and I et a feeling, but it is pretty shallow. I have a deeper understanding of theatrical forms, but in truth, I should delve into it on a much deeper level.

I am writing an article about American Community Theater for a newspaper. It is interesting stuff.
Ps. The Guardian by Barry Herem