You have some options:

• A staff person can go with you to the shelf location and see if they can find it
• A staff person can check on the carts of books waiting to be shelved
• Look around the floor where your book is supposed to be. You might find the book sitting on a table or by the copy machine

If these options don't work, the book may be missing. Let a staff person at the main Circulation (checkout) desk know. They will change the status of the book in the catalog.