Tony Duggan wrote:

>... Look at things this way: In fact, Mahler wrote only one symphony.  But
>it has eleven "movements" and the eleventh movement was left unfinished.
>In other words, his whole output was one gigantic work.

Well put, Tony-- One of my favorite remarks about Mahler's oeuvre is
that of Pierre Boulez, made some 30 years back in the preface to the
Philharmonia miniature score from the early 1970s of Das Klagende Lied.
I've quoted this before, but it's not bad to reread from time to time.

   "This first Mahlerian epic makes us aware of future devlopments and
   implications.  The great novel is sketched; we will read its chapters
   progressively in the works to come.  Thus there are creators whose
   power, springing from a single source, is amplified according to
   certain constants: this is how Mahler appears to me."

 [translated Felix Aprahaminan]

Best-Joel