Books about the same subject are assigned the same shelfmark number. You'll find the number on the spine of each book.
Here is a selection of shelfmarks for subject:
Audiology (General) 617.89
Cochlear Implants 676.882
Hearing (anatomy) 611.9
Hearing (physiology) 612.85
Hearing Aids 617.89
Below is a selection of the new subject books that were added to the library collection last month.