Aaron Copland’s book was first published in 1939 and was aimed towards listeners of American and European Classical music. He makes a lot of references of very specific music pieces by both commonly-heard and obscure composers even going as far as recalling specific movements. If these things don’t bother you or if you can read around them, I think there’s a good amount of music theory that might actually influence the way you listen to music and what you start hearing in it.
The book is broken into chapters, the most important of which beginning with the fourth. Rhythm, melody, harmony and tone color are interesting chapters that introduce the more technical aspects of music-listening like meter, pitch and how notes and harmonies are formed.
I recommend it to anyone who wants a little brain workout. It’s not organic chemistry, but unless you already have a basic understanding of music theory it might make you stop and think for a little bit. If you do want to read something that will really make your brain stretch, I’d go for Godel, Escher, Bach: An Eternal Golden Braid, a book about the intersections of music, art and mathematics.