[comethalley]

I'm fascinated by how harmony was used by the composers who first stretched tonality to its limits without abandoning it, such as composers ranging from Mahler and Strauss to Debussy and Ravel. I also feel that I don't have a solid grasp on the theory behind their music. Do you know of any books that specifically (or in part) describe how extreme chromaticism works for such composers, from a theoretical perspective and/or the perspective of composers trying to imitate it?

Many thanks!

 

[millionrainbows]

Try books by Persichetti, Hindemith, Howard Hanson.

 

[Phil loves classical]

I always recommend studying Bartok’s Mikrokosmos. Which preps the student on playing and hearing modern harmony. The harmony, etc. are dead simple to follow, although musicologists don’t agree on approaches to his music.

 

[athrun200]

I always recommend studying Bartok's Mikrokosmos. Which preps the student on playing and hearing modern harmony. The harmony, etc. are dead simple to follow, although musicologists don't agree on approaches to his music.

His Mikrokosmos reminds me of all those aural training I had several years ago. I knew Bartok through his atonal piano music (Among all those atonal music composers, Bartok's atonal music is the most pleasing to my ears).

Back to OP's question. Textbook recommended above by millionrainbows is definitely a good start. But it seems your ultimate goal is to imitate certain composers. Then the most direct way to study is to look at their composition directly. Later, you will discover how different is music theory and real music.
Music theory is just analogous to grammar in language. People didn't invent grammar before language, it's just a theory developed later to help understanding languages. The same goes for music. Without knowing every single grammar of your native language, you can still speak, write and read. Same goes for music too.

 

[EdwardBast]

Neo-Riemannian theory is essential in explaining how much of the music of this period works. The references at the bottom of the Wiki article are an excellent place to begin:

https://en.wikipedia.org/wiki/Neo-Riemannian_theory

 

[VishnuB]

These two books are the most pellucid music-theoretical monographs I have ever come across-I cannot recommend them highly enough:

Musical Structures in Wagnerian Opera

Hanbdook of Harmonic Analysis

Leland Smith's book (Handbook of Harmonic Analysis) covers tonal harmony all the way through to its dissolution whereas Marshall Tuttle's book (Musical Structures in Wagnerian Opera) focuses on Wagner but reveals a great deal about the tonal system that is not talked about elsewhere as far as I know.