Jovino just offered a fascinating seminar on minor 251s. In it, he mentioned a book by Victor Zuckerkandl, Sound and Symbol. If you’re interested, you can get it on Amazon for $47.45 (Kindle) or $49.95 (Paperback).
Or you might consider subscribing to Scribd, a reading service that offers unlimited access to sheet music, ebooks, documents, audiobooks, articles, and podcasts for $9.95 a month. Sound and Symbol is available for viewing or download in the Documents section.
Obviously, if you like to read, this site is well worth the money. But for PianoGroover’s 
it has a wealth of useful stuff ranging from lead sheets/transcriptions/songbooks to most of the best-known texts on theory and harmony to biographies and histories of musical figures and genres. And you can either access it online or you can download the material to your device(s).
I mentioned this in a thread a few years ago. I just thought with Jovino’s reference I’d share it again. It’s been interesting and fun. Among other things, I’ve read a social history of samba, a history of bossa nova, a biography of Jobim written by his sister, and a great biography of Theolonius Monk. There’s something there for whatever interest.
Scribd offers a free 30-day trial after which a subscription is just $9.99 per month