It’s not necessarily inevitable to adopt a theory for your art.
However, it enables you to give an answer to “why” question sometimes.
(It also gives you an opportunity to pretend superficial though…)
This book is known as the best introduction to abstract art and composition.
But personally, it’s more interesting to see artist’s personal, emotional and non-scientific way of observation to understand a basic rule of visual form.
by Wassily Kandinsky.