Q. I tried to renew 2 books that I have but it stated that the books were in use by the system. What does that mean?

An item or persons record can only be edited (updated) from one place at a time. If you were viewing your record and then tried to renew the items on a different page, the message would appear "item record in use by system". If you didn't have your record open on another page it could be that the records were in use by someone else; this does happen though not very often.