Versioning in Excel
 

I use Excel 2002 and I wish to perform versioning, just like is possible from
the file menu in Word 2002 - i.e. I want to save versions of a workbook
within the same file as I continue working on it in order to have the option
of reverting to an earlier version if I wish to undue a large number of
amendments - saving multiple copies of the workbook wastes file space and is
cumbersome to manage - that's why the versioning option in Word is so good -
but I want to be able to do the same thing in Excel - is it possible, or
might it be a considered function for future versions of Excel?