To add this Object to your List, navigate to:
  1. Navigate to Lists > Manage Lists
  2. Click the Manage basic and advanced lists block under List Actions
  3. Search for the List Title you would like to edit
  4. Click Edit
  5. Within Select Objects under Constituent Information select User Detail
  6. Select the Display Fields Tab
  7. Click Select Fields
  8. Expand  User Base  > User Detail and mark User Name
  9. Click Save