Any good books to formally study advanced counterpoint and harmony?

[hmrichter]

Some good ones to study that are fairly well known are preferred (so that I can get them from my local library and then be able to return it without spending $50+). Thanks!

[coda_colossale]

Can you explain in more detail what kind of a book you are looking for? What level are you at? Are you looking for a book on 16c or 18c counterpoint? etc.

Nevertheless, I recommend you to just quickly study Gradus ad Parnassum and do some Lavignac.

I have the following books:

Piston- Harmony&Counterpoint
Aldwell&Schachter- Harmony&Voice Leading
Kennan- Counterpoint
Oldroyd- The Technique and Spirit of Fugue
Kostka-Payne- Tonal Harmony
Schönberg- Structural Functions of Harmony&Theory of Harmony
And of course Gradus ad Parnassum.

Piston is always reliable, but may not always the best choice.

I recommend:
Kennan- Easy to understand, easy to find, and is a standart.
The Technique and Spirit of Fugue: May be hard to find, but I find it to be the best book on the topic.
Aldwell&Schachter- Harmony&Voice Leading: Very deep and thorough. Challenging to read.

[quantum]

Personally I like the Aldwell & Schachter.  Pairing it with a keyboard harmony text such as the following may be helpful:
https://www.amazon.com/A-New-Approach-Keyboard-Harmony/dp/0393950018