Yes; create a little form (let's call it frmCrit) with an unbound
Combo Box cboMyCombo, allowing the user to select a value to be used
as a criterion.
In your query use a criterion of
=[Forms]![frmCrit]![cboMyCombo]
Note that the form must be open when the query runs; it's convenient
to base a Form and/or a Report on the query and put a command button
on frmCrit to open that form. The user need (indeed should) never see
the query datasheet.
