The Art of Electronics is useful as a reference, certainly.
Using it to learn circuit design (just at the schematic level, still) would take serious effort (hundreds of hours) and would be far more effective if done with a skilled instructor.
There used to be simpler, smaller books that showed a simplified design process for circuit building blocks.
Rod Elliott's website, sound-au.com, has an extensive section on "theory" at the hobbyist level[1]. If you use it, please donate to help Rod keep the site up.