Copyright law in the United States stems from a Constitutional grant of authority to Congress "to promote the progress of science and useful arts, by securing for limited times to authors and inventors the exclusive right to their respective writings and discoveries." U.S. Const.Art. I, Sec.8, Cl.8. To exercise that power, Congress has enacted the U.S.Copyright Act, codified in Title 17 of the U.S. Code. Under that Act, the United States grants copyright protection to original works of authorship that are fixed in a "tangible medium of expression". Once protected, copyright owners are granted certain exclusive rights--for example, the right to control reproduction and public distribution--over the copyrighted work, subject to some limited exceptions for user.
Secondary sources can give you an overview of the application of the law, some history, citations to primary sources, and analysis on unsettled points of law. Treatises can be an especially good choice for copyright law research because there are several that closely track the Copyright Act and provide citations and analysis of nearly all primary law on point. The following three treatises are generally regarding as the leading authorities:
Deskbooks and practice guides are another good place to start your research, especially if you are unfamiliar with Copyright Law and need a straightforward introduction to this area of the law. These tools can also be especially helpful for understanding how to address practical issues such as filing registrations with the Copyright Office, drafting industry-specific licensing agreements, or drafting cease-and-decist letters for specific uses. Some of the most useful titles in the UNC collection include:
The United States Copyright Act is codified in Title 17 of the United States Code. The text of the Act, including amendments, is available online in a number of places, including freely from the U.S. Government Publishing Office, the U.S. Copyright Office, and from the Cornell Legal Information Institute. Title 17 has been enacted by Congress as a positive law title, meaning that this U.S. Code title is legal evidence of the law (read more about the distinction between positive law and non-positive law titles here).
While free versions of Title 17 are available online, for most serious research questions it will be more efficient to access this Title through subscription databases that offer citator services, listing cases, regulations, and secondary sources that cite to particular sections of the Act. Two of the best and most frequently used are WestlawNext's KeyCite, Lexis+'s Shepards Reports. Those two services also offer statutory annotations ("Notes of Decision" in Westlaw Next, and "Annotations," located at the bottom of the screen, in Lexis+) which categorize and summarize cases that have interpreted specific statutory text. As with any statutory research, consider using the table of contents and internal cross-references rather than just full-text searches to help guide your research through the statutory scheme enacted by Congress.
Title 37, CFR contains regulations covering patent, trademark and copyright. Although a highly technical area of the law, the regulatory authority of the Copyright Office is limited and so regulations covering copyright are minimal, mostly covering the process of registration. Title 37 is also available online through the US Government Publishing Office (PDF and e-CFR) and from the Cornell Legal Information Institute.
Although not carrying the force of law, the U.S. Copyright Office maintains several helpful guidance documents and explanatory publications to help practitioners and the public understand how the copyright office functions and how copyright law applies.
Unlike patents, copyright interests need not be registered or recorded to take effect. However, registration carries significant benefits for copyright owners (for example, access to substantial statutory damage awards in the case of a successful copyright infringement lawsuit) and so many commercial works and other important works are registered with Copyright Office. Full records for older works are not yet available online, but below are some good sources for information about registration records: