A book may be just a few centimeters off its intended spot and is essentially lost. The catalog says that the item is available, its call number is correct and the spine label is readable but the reader cannot find it. It may be that the book is shelved between the wrong books. Shelf order is not a secondary aspect of library operations; shelf order is the link between the catalog and the collection and is essential to effective book retrieval.
To get a sense of how easily a misshelf might occur, place ten sample spine labels on a shelf in their proper order. Then take two labels from different books and put them in nearby incorrect places, reading from left to right. Look at them slowly without actually touching them. Misplaced books can be hard to spot, particularly if the beginning of the classification number is the same or if the author marks start with the same letter. Next, compare only two adjacent labels and read the order. This may be easier to do and the misshelves that are missed when one reads the entire list are likely to be caught.
Shelf order may change easily with usage. Some books are returned not to their call number location but to the location of the title, or perhaps a thin book is returned behind a thicker one, or perhaps a title of a multipart set is returned to the wrong spot in that series, or an “oversize” book is returned to a call number location that differs from its shelving location. A crowded shelf, a missing or faded spine label, the use of temporary shelf markers, or other factors can change the placement of books from what is in the catalog. This may occur even if there is no error in the call number.
Begin to carefully read a shelf by understanding the rules of shelving in the collection that is being read. Read the classification number first, reading from left to right and considering each digit as a number, rather than considering the call number as a whole. Next, read the author mark and then the title mark, volume number, year, or copy number as used by the library. Different libraries may have different conventions to use; know how that library arranges a shelf before attempting to correct misshelves. If the spine label is unusual in that particular sequence, check the catalog record and the item record rather than shelving the item in a location different from that suggested by the spine label. The spine label may be incorrect, partially missing, or damaged.
Shelf read short segments and leave the items in a known place if you are removing books from the shelf. Removing several books that may not be correctly shelved can lead to a new shelving problem. Document things that you cannot resolve or fix immediately, including a spine label missing, the call number of the book differing from the catalog record, the item was found in the wrong collection, or a book is marked as “available” but it is missing. Keep a record of any corrections, especially to differentiate reshelving from the need to change the catalog record or change the spine label, note a book’s condition as poor, or mark the record as missing.
If a section is orderly, the next item on the shelf is likely to match the sequence of classification numbers and author marks. Stop briefly, then read the spine label of the next item in the order before you look at it. If it matches the predicted sequence, then perhaps the shelf is in good order. If it doesn’t match, stop at that item and check the location of that book and the previous book against the catalog records. This small break can make a difference in locating a missing book.