Hi Richard,
To get the information for the worksheet your formula is on. you
want to use the cell reference
=CELL("filename",A1)
You can get the pathname information for another sheet
=CELL("filename",sheet1!A1)
The crippled form without the cell reference
=CELL("ffilename")
will give you the name of the sheet
from the last sheet update, which may be another sheetname, or even in
another workbook. For more information see
Pathname in headings, footers, and cells
http://www.mvps.org/dmcritchie/excel/pathname.htm
and you can test that for yourself.
The CELL formula is not effective until the workbook has been saved
so you have a pathname reference.