Good Harmony books out there?

I don't know Perischetti's book, but the 2 books are dealing with different subjects. Piston deals with traditional "Common Practice" harmony which is the harmony empoyed by Bach, Mozart, Beethoven, Tchaikovsky, etc. up until about 1900.
By the turn of the 19th/20th century, new concepts were being introduced, such as atonality, serial composition, etc. This is what is now broadly referred to as "20th century harmony".

What's important to note though is that the harmony found in most rock and pop music is almost all "tonal" and relies heavily on diatonic scales, and so has far more in common with Common Practice harmony than with 20th century harmony.

So, if you're interested in learning more about keys, cadences, I, IV, V and other tonal chord progressions, extended chords, modulations, etc I'd stick with Piston or any other book that deals with Common Practice harmony.

If you're interested in the practices of modern classical composers, then the Perischetti book will deal with that.

I like Piston for common practice, mostly because it's what I used in school. Many schools today are using Kostka's "Tonal Harmony", which pretty much covers the same ground, and covers a bit more of the 20th century than Piston did - because it was written late in the 20th century, rather than in the middle of it. I don't like Kostka as much because of his naming conventions - he calls dominant 7th chords "major-minor7" chords. Although that captures what they are, everybody but Kostka calls them dominant 7ths.

I don't have Perischetti. But in studying theory, I think it helps to work from a historical perspective - counterpoint informs homophony (common practice); homophony helps you make sense out of 20th century stuff - even the serial stuff, because you know what it departed from. So I'd go with Piston or Kostka first.

One other option for modern theory is jazz. I'd recommend Mark Levine's "Jazz Theory Book", or the hard to find "Modern Harmonic Technique" by Gordon Delamont.

Thanks a lot Fretsource and Noteboat....PIston is on the way and I'll check out Levine's Jazz book!
All the best

Thanks a lot Fretsource and Noteboat....PIston is on the way and I'll check out Levine's Jazz book!
All the best

So, how is the Piston harmony book working out? Would you buy it again if you had to do it over? What do you think of the book?

Thanks

Thanks a lot Fretsource and Noteboat....PIston is on the way and I'll check out Levine's Jazz book!
All the best

So, how is the Piston harmony book working out? Would you buy it again if you had to do it over? What do you think of the book?

Thanks
HI Hyperborea.
I really recommend it. At the beginning I thought it was going to be hard to get into it, but now I found that it's not difficult to follow at all.

Hope this helps.
all the best