Listing slots in CLOS

Hi,

Is there a function, which will return a list (or whatever) of the slots
in a class that I've got an instance of? I'm working with a weird auto-
generated binding library, which I don't really understand... and I'd
like to be able to eyeball the fields I can play with!

The only things I can find are slot-exists-p and slot-bound-p, which of
course aren't quite what I'm after. If there's not a portable way to do
this, I'm using sbcl.

Rupert
.