On a form containing only 1 entry :
[myformname]![fieldname]
including this as criteria in a query finds the correct items.
The question is how to define this criteria to select the correct [fieldname] from a form with multiple entries.
At the mom this action on a multiple field form puts up a "parameter dialogue box" which I am trying to avoid.

Are you saying that your query criterion would need to match the value from one of several textboxes on a form? That sounds odd, if you explained your ultimate goal it might help me understand your problem better. Maybe there is another approach.