project. One of our requirements is to be able to fit text into a cell of a table. If the cell is not big enough to hold the text at the requested size, then I wish the size of the text to be reduced so that it will all fit into the cell. Is this possible with XSL/FO, if so where to I start?

Words of one syllable no.
XSL-FO, as delivered, has no feedback from the laid out page
back to the stylesheet.

Well, in some cases a
 font-size="$constant div inherited-property-value(width)"
might do it, even for porportional fonts.