Select the Sigma icon in the Toolbar (looks like the letter "E"). Select your Autonumber field. By default, you will see Group By in the Totals column. Change Group By to Max. This will give you your Max Autonum. Save this query. Write a new query, using your original table and the query that you just wrote. Tie(Inner Join) the query and the table together on the Max Autonum field. Select whichever fields that you want to see. This query will only return one row: the record with the Max Autonum.
*edit* you can actually do this within one query by using a subquery in the WHERE clause of your Autonum field, but I don't know your SQL experience. Plus, it'll be slower as subqueries are not pre-compiled by Jet as nested queries are.
