The main collection has about 139,000 items. The reference collection has about 4,000 items. And the Children and Young Adult Collection has about 4,600 items.
It's easy to find books within the library. The Tran Library uses the Library of Congress Classification System.
If you search an item in the library catalog and the item is available, then you can find the call number to locate the book.
"Forest Grove Main Collection" tells that the item is in the Main Collection (the other collections are Reference, Historical, Music, Young Adult & Children, and Course Reserves).
Then you can go to the next part. This gives the exact location of the item. PS3609 is the first part you would look at. Then V54 narrows down the section to a small group. S66 narrows that even farther. And 2012 would bring you to the exact item.
The call number is a sort of map telling you the location of the book within the library.