@b0rk related to the mostly lack of structure is that the ASCII spec gives functions for all of the control codes, and these mostly have nothing to do with how they are used by Unix terminal programs. The ones where there is a connection are ^H and ^? (backspace), ^J and ^M (newline), ^I (tab), ^L (form feed / clear and redraw) ^G (bell / beep), ESC (escape), and debatably ^D (end of transmission / pseudo-end of file).

You said you didn't want a history lesson but if you decide you're curious the place to start is the monograph "The Evolution of Character Codes, 1874-1968" http://falsedoor.com/doc/ascii_evolution-of-character-codes.pdf