Salem State University Library uses Library of Congress call numbers.
Here are some useful call number ranges:
D:World History
F: History of the Americas
L: Education
P: Language and Literature
Search for Harry Potter as TITLE = All books with Harry Potter in the title. Examples: Harry Potter and the Sorcerer's Stone, 101 Amazing Harry Potter Facts.
Search for Harry Potter as SUBJECT = All the books about Harry Potter. Examples: Heroism in the Harry Potter Series, Harry Potter and International Relations.
Search for J.K. Rowling as AUTHOR = All the books Rowling wrote.