If something is currently unavailable/checked out, you can usually place a "hold" on it.
If you want to be notified and have the item held for you when it is returned (and prevent it from being renewed), click on “Place Hold”. For "Username" enter either your Student ID or the Barcode number of the back of your ID. For "Password" enter your last name and click on “Go”. This will bring you to the hold form.
The only information you need to supply on the hold form is the "period of interest." If you want the book as soon as it is returned, use today's date in the "from" field, and put your last possible need-by date in the "to" field. It is not necessary to fill in the other fields.
You will be notified by email when the item is available for pickup.