Improvising in western music is not a new thing; it just became unfashionable in nineteenth-century classical music. Back in the eighteenth century it was very popular: one of Bach's most well-known pieces, the Brandenburg Concerto No. 3, consists of three movements but only two of them are written out in full. The written music for the middle movement is just two chords long—which would only last about ten seconds. It is possible, of course, that Bach was called away in the middle of his writing to take part in the birth or, indeed, conception, of one of his twenty children, and forgot to finish it. The more traditional historical view is that the second movement would consist of a three-minute viola solo by Bach who would then nod at the rest of the band—and they would finish off with these two chords. Nowadays, in most recordings of this piece, the musicians chicken out on the improvisation and just play the two chords—and who can blame them? I certainly wouldn't want any of my own improvised drivel sandwiched between two pieces by Bach.

—John Powell, How Music Works