In his last comment, Quantz goes to the heart of the problem. We have
very little knowledge or understanding of the structure or purpose of
the cadenza in the classical concerto beyond its elementary definition as
an improvisation on themes from the movement. Amazingly enough,
there is no provision for it in modern theories or descriptions of concerto
form. Even though concert artists may well undertake to compose
cadenzas for Mozart and Beethoven concertos, or at the very least,
choose among those already composed, conservatory training does not
normally include study of the cadenza problem. Yet it seems obvious
that to write satisfactory cadenzas, the performer should understand
what relationship one should have with the concerto movement. In view
of both new theories and conceptions of the classical sonata style, to