Why do you have two tables like this? It sounds like you might not be
following normalized database design. What differentiates a person in one
table from the other? Probably (but not 100%) you should have all of these
folks in one table and a new field to differentiate them.
Post back more details and we can help you normalize your data and save you
a lot of heartache down the road.
If you are not interested in normalizing and simply want an answer to your
question, you can create an UNMATCHED query to find all records in one table
that are not in the other. The query wizard offers this option and will
walk you right through building it.