The 12-tone method of composition was created by Arnold Schoenberg during the span from 1920 to 1923. It soon became the leading way to compose atonal music. From here on in the discussion may get a bit technical, so you might want to brush up in our music theory section if you start finding yourself confused...
The whole idea behind atonality was to do away with the tonal system that had governed virtually all music up to that point. The notes in a tonal piece were organized such that every note was heard in terms of its relation to the key of the piece. So if you wanted to write an atonal work, you would theoretically have to do it so that no pitch could be heard as the key center of the piece. That is exactly what the twelve-tone method did.
The principle behind twelve-tone music (or dodecaphony, as it is also called) is that no one tone can be repeated until all eleven others have also been heard. This way, the tones are now interpreted in terms of their relation to each other, and not to any one key tone. This was what Schoenberg had in mind when he originally called the system a "Method of Composing with Twelve Tones Which are Related Only One with Another." The technique makes it impossible for any one tone to assume more importance than any other.
The attitude behind the twelve-tone method is well summed up in the words of Schoenberg's pupil Alban Berg: "Just as the church modes disappeared and made way for major and minor, so these two have disappeared and made way for a single series, the chromatic scale. Relation to a keynote, tonality, has been lost... Earlier, when one wrote in C Major, one also felt "tied" to it; otherwise the result was a mess. One was obliged to return to the tonic, one was tied to the nature of this scale. Now we base our invention on a scale that has not seven notes but twelve."
It's important to remember that the twelve-tone system has been
refined and varied by different composers, much like the
traditional methods of composition had also been changed and
modified. Therefore, there are now many variations of it out there.
You should also note that setting tones to a series of numbers was
only the beginning... serialism later
adapted the practice to determine not only the tones, but for just
about every other musical aspect as well.
"So how does it all work?" you ask. To illustrate, we've come up
with a cute little guide to using the twelve-tone technique. To see
the animated Flash
4 version, click here. If you
don't have Flash 4, you can go to the text version by clicking