This June, I’ve been taking an online course for my library science degree–Introduction to Classification, which covers the tedious world of library classification systems aka how they keep track of all the books.
I’m most familiar with Dewey–it’s the most widely used system. It’s numbers based. So first, you have to figure out which class the discipline of the book best corresponds to.
000 Computer science, information, library science
100 Philosophy and psychology
300 Social sciences
700 Arts and recreation
900 History and geography
Once you’ve figured out the class your book belongs to, say the 800s, then you move to the second digit. 810 is American literature in English. 813 is American fiction in English. Then you can add a decimal point after 813 and continue on to the Tables, which have Standard Subdivisions, divisions for geography, divisions for works by individual authors, languages, etc. I find the tables pretty confusing still.
Then there’s Library of Congress subject headings and classification. LoC is, of course, used in the Library of Congress but it is also used many academic libraries. LoC subject headings are a bunch of authorized subject headings that are applied to books; they are controlled vocabulary, meaning the headings aren’t just willy-nilly.
From that class’ homework assignment:
I sort of compare them to the categories your book can go into on Amazon lol. Library of Congress also has call numbers, which usually begin with a letter (K for Law, for instance), then numbers, then a decimal point, and more numbers.