Helping a patron find a book is a hard proposition sometimes. It's so rare that we do it now in the age of ebooks and ejournals and enonsense. Still, some people do need to find a physical copy to dirty with their dirty hands. Here's the steps you should take to find a book for a patron.
1. Determine the exact title and author
Sometimes the patron knows the item they need. They come to the circulation desk, slam down a wad of paper and say, "Pillow Monsters by Abraham Funkytown, please." Then you can look up the item and determine that it is in the library. If the patron does not know the exact title and author, well, you could question them or just guess. Guessing is fun. Also, Amazon has a lot of stuff so you could find the spelling there.
2. Determine if your library has the book.
Find the title in the computer box. You did that and it rewarded you with a location. That location will tell you where to find the book. Because that's how locations work. Never point to the location of the book, no matter if its an easy book in a dump bin. Always walk the patron to the location, filling them with tidbits like "this is where we keep the books."
3. Give them the book (if you can)
Two things can happen when you walk into the stacks to find a book*. You find the book or you don't find the book. Schrodinger's book until you make it to the shelf, if you will. Finding the book is easy: just give it to them, dummy. If you don't find the book, though, well…
4. Double check all the places it could be
As the philosopher John Bender said, "Screws fall out all the time, the world is an imperfect place." This includes books as well. Books can fall behind other books, be misplaced on other shelves, been picked up and placed on a table. Exhaust all options. Check all the places, including transposing all letters for numbers in the call number**.
5. Check the cataloging department
Go back to the cataloging department. Those assholes sometimes grab books as they come in or pull them from the shelf for whatever mystical reason without updating the system***. Do not allow the patron to follow you into this den of thieves and liars. If you must, kneecap the patron to keep them from following you. Say, "I'll be right back" in your most confident tone.
6. Place a hold
Everywhere has been checked for the book, even in your own hands and the pocket of your jacket. The book cannot be found. Time to pass the buck. Tell the patron you will place a hold on the item for them. Most libraries have a list of books that patrons are looking for or are too lazy to get on their own. These lists are checked daily by library peons who often with their fresh eyes find books easier than you can with a crying patron following you. Go figure.
*Okay, actually there are nine, but most of those are fantasies involving Neil Gaiman, Karen Gillan, Idris Elba, or a combination of the three.
**When typed out, 5's look a lot like S's, 8's can become 0's or O's, and in very few circumstances "&" can become "=."
***Their excuse is often "nobody wants to read that shit."