Johann Sebastian Bach
"Das Wohltemperierte Klavier"
1000 Recordings to Hear Before You Die
The ultimate lesson in Bach's discography is that the composer couldn't write anything without it being historically monumental. Sure, Bach's grander Baroque contributions (such as the Brandenburg Concertos that we already examined) were great. Ultimately, his greatest contributions might be from the educational standpoint however. The purpose behind his Sonatas and Partitas for Solo Violin (the last Bach we looked at) was not an educational one, but its overarching grasp on Baroque techniques make it a standard for violin players today. Das Wohltemperierte Klavier (or "The Well-Tempered Clavier," as it will be referred to from this point) was actually intended as an educational tool for pianists in training.
There were only so many people who could afford a piano or similar instrument at the time, so young piano players came from wealthy families. As there were so few pianists, there were even less who were qualified to instruct. Composers like Bach could only depend on patronage so much, therefore they filled their time teaching aristocrats the art.
Bach's Clavier was especially relevant because it's the first collection that contains movements in all 24 keys. Previous composers had also contrived similar compositions, but not with as wide a reach. This collection is also relevant for when it occured. At the time, equal temperament was on the rise. Equal temperament is a method of tuning in which every pair of adjacent notes has the same frequency ratio (this is the modern standard tuning). Meantone temperament (the other option) forms a less-perfect scale. Bach's title suggests that the piece is meant for well temperament, a method of tuning that allows a piano to be played in all keys without sounding out of tune.
It's not necessarily important, but it certainly is interesting to mention that there's no authoritative proof that Bach intended of the Clavier to be performed in well temperament. Most concur that the official title is unquestionable evidence of his intents. However, during much of the 19th century, experts presumed that Bach intended it to be performed in equal temperament, the rising trend at the time. Bach left no hints aside from his title; the composer preferred tuning his own instruments, and there are no records as to how he did it. Well-tempered is the current popular tuning, but Moon seems to favor the equal temperament argument. Others have even wilder theories (see "Interesting Fact").
The actual music is a demonstration in form and function, much like Bach's solo violin entries. Each step in the standard piano tuning alignment gets a prelude and a fugue in both major and minor (totaling 24 pairs for those unfamiliar). The preludes serve as the form; more convivial than its partner. The fugues are a more straightforward exercise in contrapuntal playing; giving both hands a workout that winds back to the original theme.
So it's good exercise, but is it good for enjoyment? If you're a piano nut, certainly. Don't get me wrong; It's a worthwhile listen but most will prefer an orchestra backing the pianist. This probably sounds terribly shallow to a piano purist, but this is wonderful study music.
INTERESTING FACT: Music scholar Herbert Anton Kellner suggested that the the proper temperament was hidden within the design on Bach's signet ring, and could be solved using numerology. Surely Dan Brown could spin a book out of this, or perhaps "National Treasure 3: Bach's Baroque Booty." Booty as in treasure, clown.