This document provides an overview of copyright law and how it relates to libraries. It discusses the origins of copyright law in the US Constitution and the first Copyright Act of 1790. It summarizes the major revisions in 1831, 1870, 1909, and especially the Copyright Act of 1976 which forms the basis of current US copyright law. The document explains the US Copyright Office and key aspects of copyright law such as public domain works, penalties for infringement, and who owns the copyright. It focuses on how fair use and Section 108 of the copyright law allow libraries to make copies for purposes like preservation, private study, and interlibrary loan within certain limits and guidelines.