This document summarizes some key differences between K-12 school libraries, academic college libraries, and public libraries. It notes that school libraries are only open during the school day and have smaller collections arranged by Dewey Decimal, while college libraries stay open later and longer during exams, have collections tailored to campus courses/research, and may use Dewey Decimal or Library of Congress classification. College libraries also typically have multiple service desks and larger collections than K-12 libraries.