genre (noun)

: a category of artistic, musical, or literary composition characterized by a particular style, form, or content

subgenre (noun)

: a genre that is part of a larger genre

Genre should not be confused with format. Genre is about content, whereas format is how the story or information is presented. Traditional print books, novels in verse, and comic books are formats that include many different genres.

The Mahoney Library holds about 7,000 books. About half of those are nonfiction books and about half are fiction.

NONFICTION

Nonfiction books are organized by Dewey Decimal Classification, which is very common in school and public libraries and organizes books according to discipline:

• 000 : Computer science, information & general works 
• 100 : Philosophy & psychology
• 200 : Religion
• 300 : Social Sciences
• 400 : Languages
• 500 : Mathematics & science
• 600 : Technology & applied sciences
• 700 : Arts & recreation
• 800 : Literature
• 900 : Geography & history

FICTION

Fiction books in the Mahoney Library are organized by genre, according to popularity with Mahoney students.

• Realistic Fiction
• Historical Fiction
• Mystery
• Horror
• Science Fiction (Sci-Fi)
• Fantasy
• Sports Fiction
• Animal Fiction

The Map of Literature by Martin Vargic. (Very) large version here.