I have read two great books that have helped me better understand audio and music. They are:
(i) Perfecting Sound Forever: The Story Of Recorded Music by Greg Milner
(ii) How Music Works by David Byrne
What are your favorite books about audio and music?
It is probably out of print at this point though I am sure you will be able to find used copies online, but Good Sound by Laura Dearborn from 1987 is an excellent book for those looking to get in to high quality music playback.