Default pathnames

[bloch@informatics.wustl.edu (Charlene Bloch Abrams)]

(I seem to recall having skipped over relevant/related discussions recently;
if so, could someone please mail me a copy of said discussion).

I'm using (choose-file-dialog) to pick a file, but what I really 
want is the pathname. (choose-file-dialog) has a :directory keyword
which accoding to the manual "defaults to the last directory shown by
the Chose File dialog box or Choose New File dialog box" - how do
I find out what this is? Or is there another way to find out where this
file that has been chosen is?

Once again, any and all help and/or pointers appreciated.
Charlene