The “key” of a music seems like a mystery, but it really is not that huge of a deal. Even when the performer him-self does not invent, or improvise (as was the case up to now and in most modern-day performances of music by preliterate peoples), however more or less freely reproduces the music invented by others (learned by ear in people music and in Oriental music), or precisely performs music written by others (res facia, within the Center Ages), an inter-private course of takes place.

The musical theater of the people took several types: the bagatelliste drama, the commedia delL’arte, and the Singspiel. Simple classical pieces and many pop and conventional music songs are written so that all the music is in a single key. In America there developed the musical comedy, designed as mild leisure in a well-liked musical idiom.

Involvement in playing and singing music is assumed …