Columns in your Inbox and in other table views of message lists are known as fields. To restore a column in these views, you need to add the column or field back to the views.
On the View menu, point to Current View, and then click Customize Current View.
In the Available fields list, click the field that you want to add.
If the field that you want is not in the Available fields list, click a different set of fields in the Select available fields from box, and then click a field in the Available fields list.