Reserving a book is only possible when there are no copies currently available in the library.
When you reserve a book, you will be put on a waiting list, and it is only when copies are returned to the library that one will be put aside for you. You will then be emailed to tell you that you can collect the book.
The example below shows a book that can be reserved. In the bottom right, there is a green "Reserve this Item" button which will bring you to the sign-in page if you have not already signed in. You should choose the Single Sign On option on the left and then click Reserve once more to complete the reservation.
If there are copies of the book available then this green button will not be available and you need to come to the library and take out the book.
