Ted,
You can do this with the query builder in EG.
1. Add both tables to the query builder. (Let's call them TABLE1 and TABLE2). Add the desired columns to the "select" list.
2. In the Join window, make sure that the tables are joined on the key column you want. (Ex: TABLE1.column and TABLE2.column)
3. Modify the Join type to Outer Join (last selection in the list of join types)
That specifies that you want all rows from both tables to be considered for the result set. Now you want to create a filter so that you get only those rows with a value in the first table and NOT in the second table. So...
4. Create a filter: where TABLE2.column IS NULL ("IS NULL" is a selection in the filter operator list)
That should get you what you want.
Chris