DSSSL documentation project. This is still growing, but
there's already a fair amount of useful stuff, including the
outline of a
DSSSL Handbook
(little more than that as yet, but it appears to be growing, and looks
as if it will be useful when it's more nearly complete).
Paul Prescod. Very clear (even if it sometimes has
overtones of Play School about it `now let's try to...'); also
pretty compact, going from assuming nothing to non-trivial programming
in a fairly short time.
A tutorial on DSSSL's Core Expression Language is really
more of a quick reference than a tutorial, but is useful for that. At
the same place, the DSSSL
cookbook is just that - a collection of snatches of code
to do useful things.