If you receive an email notifying you that one of your books has been given an earlier due date than the one given when the book was issued to you, someone else has recalled this book as they need to use it. When you borrow an item, the due date is "subject to recall"; if the book is reserved by someone else, then we will ask you to bring it back early and notify you of the new due date for the item. You need to return the book by the new date to avoid having to pay overdue fines.
For more information:
http://www.dur.ac.uk/library/using/borrowing/holds/


