Sortable Columns - each column is sortable by clicking the column headers 
Click on the column header to sort the table by that column.

The first click will sort the column in ascending order (A-Z or 0-9) and the second click will re-sort the column in descending order (Z-A or 9-0).  By clicking the column headers you can easily toggle the sort order.

Note: When you click a "Alphabetic Index" character, the Last Name column is automatically sorted in ascending order A-Z.  If  it doesn't sort correctly, just click the Last Name heading until the column is sorted in ascending order A-Z then try the "Alphabetic Index" character again.