I need some help deciding on a Chess book

I have several chess books so far, but what I need is a book on chess theory. I have no idea how to look for weak squares, attacked squares (not the obvious) and such. I can follow openings in MCO-14, but unless the piece attacks another, or tries to control the center, I really don't know why that is the best move.

I am pretty good at chess puzzles, and I have countless games that I could play through, but I feel I am lacking a foundation of the theory behind the game. If you asked me to Identify Black's weakest square, I wouldn't know where to start.

Any ideas?
tony

Siman's "reassess your chess","The amatuer's mind" or Nunn's "Understanding chess move-by-move" or Nimzowitsch's "My system".All very good books,though "My system" is difficult,at least,to me it was.😴