Reddit reviews A Practical Approach to Eighteenth-Century Counterpoint

If you think you are ready for some heavier academic writing on music theory, here's how you can get into it:

1. Music Theory Online, the free, peer-reviewed journal created by the Society for Music Theory. It's convenient and very legit. Some articles have animations, videos, and sound linked right there.
   
2. Look at the award-winning publications list on the Society for Music Theory website. If something piques your interest, get it! Either from Amazon or from a university library (or really, really good public library).
   
3. If you go to university, you probably have access to JSTOR—a huge database of academic articles, including articles about music theory—through your university's library website. The big journals are Music Theory Spectrum and Journal of Music Theory. You can also check out Intégral, Theory and Practice, Perspectives of New Music, Music Perception, and way more on JSTOR.
   
   I would also recommend getting familiar with counterpoint and set theory, if you haven't already! My recommended books on counterpoint are by Robert Gauldin, A Practical Approach to 18th-century Counterpoint and the 16th-c. version as well. It's called "a practical approach" because Gauldin does not teach via the species method. (I tend to find species unrelated, anyway—species counterpoint is a good and important exercise, but not exactly the same idea as 16th- or 18th-c. writing.) For set theory, I recommend Joe Straus's Introduction to Post-Tonal Theory. It's expensive for such a small book; unfortunately, this is a fact of life for any book about 20th- and 21st-c. music, since copyright laws make publishing them quite expensive. You might be able to find older editions for cheaper.

I found Robert Gauldin's books on 16th & 18th-Century Counterpoint very easy to read and fairly inexpensive.

http://www.amazon.com/Practical-Approach-Eighteenth-Century-Counterpoint/dp/0881338532

Wonderful introduction to the subject and much more.

Read through every fugue you can get ahold of by J.S. Bach (almost a cliche response, I know). Obviously, studying the Art of the Fugue and the WTC thoroughly will teach you more about practical application than any book. But, it is always useful to view the subject from differing viewpoints.