As a performer one should always try to get as close to the source as
possible.  In the case of Bach's Six Suites for solo 'Cello this is not
so easy.  There are two common frames of reference that most editions draw
upon.  The first is a somewhat careless copy by Anna Magdalena Bach.  The
second by the organist J.  P.  Kellner (1705-1772), an acquaintance of Bach
and only exists today by virtue of the fact that it is incorporated into
the Bach-Gesellschaft Edition (volume 27).  The extent of how subsequent
editions draw on these sources does however vary.  The suites were written
during Bach's Cothen period (1717-1723).  While it is true that the great
Spanish 'cellist Casals did bring them to the attention of the world
through is public performances and recordings (although he never edited
them) the suites were known long before the Casals recordings which date
from 1936-39, keep in mind the fact that Casals was born in 1875.  Before
the year 1900 no less then seven editions were in print and that is just
the tip of the ice berg.  From 1900-1950 at least another twelve were in
print and that number has gone way up in the intervening years.

One of the problems with the "source(s)" is that they provide little if any
guidance as to dynamics and the same holds true for bowing and articulation
so in a manner of speaking the suites present a kaleidoscopic range of
interpretive possibilities to both the performer and the editor.  Some
editions like the Barenreiter of 1950 (Wenzinger) are extremely scholarly,
suggest bowings and some fingerings and also, and this a big also, foot
note any changes, i.e.  differences to the "source(s)".  The majority of
the editions of the last fifty years are what I would describe as players
editions, i.e.  here's the way I do it.  Tortelier, Markevitch, Kurtz,
Mainardi, Fournier, Starker....the list could go on and on.  Tortelier,
who studied the cycle with Casals is quite interesting although at times
off the wall, he does include footnotes which many of the others do not.
Starker who has recorded the cycle more times then anyone else says quite
frankly that this is the way I play these suites most of the time which is
fair game.....except when your edition contains wholesale deletions of
notes from chords etc.  In my view if you're going to do this then you
really must provide foot notes which document these changes.  Rostropovich,
who has recorded them one and a third times has, to date, left no edition.

Moral of the story, everyone plays them differently, which perhaps not a
bad thing!

Peter Schenkman, Toronto, Canada