that is why the word art is in the title. regardless, it gives you a good feel for how many engineers actually design stuff in the industry. the problem spaces aren't fully constrained, so you have to fill in the gaps with experience, guesswork, experimentation, and (yes) art.
Yes, I realize art is in the title and get the general sentiment. But this book is often proposed as a way to learn electronics from scratch. I'm not terribly sure it accomplishes that. My thoughts are that it's probably similar to the Feynman lectures: terrible to learn from as a first introduction but great once you have already learned the material.