In the past three years, everything I have learned about harmony, and I should say everything I have learned about music, has come from learning and playing the Riemenschneider book of 371 Bach chorales. This is the standard collection of German religious tunes, some dating back to the Middle Ages, from both the Catholic and Protestant traditions, as set into four-part harmony by Johann Sebastian Bach. The book in its present form first appeared in 1831.
The Riemenschneider contains many familiar tunes -- you get three versions of "Ein Feste Burg Est Unser Gott," a.k.a. "A Mighty Fortress Is Our God," composed by Martin Luther himself. You get "Befiehl Du Deine Wege," or "Entrust Thy Ways," which was later ripped off by Paul Simon and labeled "An American Tune." (Has he no shame?) Many other tunes are Bach originals or were used as the basis for Bach's cantatas.
Once again, I'm conducting my own musical education in public. I'm a nearly illiterate piano player. As a child I had four years of piano lessons, and quit at age 9. From age 15 to age 34 I played bass guitar in rock bands and never read a note. At age 34 I returned to keyboard and soon realized that if I didn't learn to read music, I'd never get any better. So I started with some elementary J.S. Bach pieces and soon found my way to the chorales. I bought my paperback copy of the Riemenschneider for $12.95 at the old Patelson music shop on West 56th Street (now gone), and it has kept me busy every day for the past three years.
It's all here -- composition, melody, counterpoint, voice-leading, phrasing. This is my crash course. Most of the pieces are very short -- 12 to 20 measures of music. And there's no end to what you can do with each one. You can find dozens of ways to play each one, staying loyal to the score, and the melodies are so strong and time-tested that they never wear on the ear. Once you get a feel for the book, open it anywhere and go to town.
I'm still a long way from being able to sight-read four-part harmony, but the gain in reading ability is another benefit I have gotten from the Riemenschneider. And that in turn helps one's rhythm, of course, giving each note its full value.
And there's more -- you learn to think in terms of four-part harmony. You get a natural feel for counterpoint -- keep the hands moving in opposite directions. Then, of course, this is the essential textbook for harmony. I'm still finding combinations of three or four notes that I have never played before.
If I'm lucky, I can get an hour or two of practice early in the morning, and I'll get to spend some time with, say, "Wo Soll Ich Fliehen Hin" ("Whither Am I to Flee"). At first, it's slow going, getting the tune under my fingers. As I'm reading the notes, coordinating that with the movement of the fingers, the brain feels fully lit up. The tune is concise enough that you can keep playing it over and over. Slowly it comes together. After a couple of mornings of this, it starts to sound and feel like music. Keep going, and eventually you just hear the tune playing itself, and you just happen to be there while it's happening. You forget you are playing. When I get to that point, that sets me up nicely for the day.