Copyright is a form of protection of "original works of authorship" fixed in a tangible medium or expression. It protects the right of authors and other creators to control the use of their work (including their right to obtain commercial benefit) for a limited period of time. 

United States copyright law was written into the U.S. Constitution. Article 1, Section 3, Clause 8 of the Constitution states that "Congress shall have the power...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." This provision is known as the Copyright Clause. Ultimately, the United States Congress established laws governing copyright use in Title 17 of the United States Code. The title was revised in the Copyright Act of 1976, and there have been several subsequent important amendments to the law. 

Copyright law was established to protect the rights of authors/creators, but also, by protecting those rights and thus allowing authors to potentially benefit from their works, copyright is meant to encourage creativity and promote progress.

Per the U.S. Copyright Basics circular: 

"Copyright is a form of protection provided by the laws of the United States to the authors of 'original works of authorship' that are fixed in a tangible form of expression. An original work of authorship is a work that is independently created by a human author and possesses at least some minimal degree of creativity. A work is 'fixed' when it is captured (either by or under the authority of an author) in a sufficiently permanent medium such that the work can be perceived, reproduced, or communicated for more than a short time. Copyright protection in the United States exists automatically from the moment the original work of authorship is fixed."

Examples of types of works protected under U.S. Copyright Law include:

• Literary works
• Music
• Dramatic works
• Choreographic works
• Pictorial, graphic, and sculptural works
• Motion pictures and other audiovisual works
• Sound Recordings
• Architectural works

Copyright does not protect: 

• Ideas, procedures, methods, systems, processes, concepts, principles, or discoveries
• Works that are not fixed in a tangible form
• Titles, names, short phrases, or slogans
• Familiar symbols
• Mere variations on typographic ornamentation, lettering, or coloring
• Mere listings of ingredients or contents

For works that are protected, copyright exists automatically from the moment it is fixed in a tangible medium. A work does not have to be published to have full copyright protection, nor is a copyright notice is required (anymore). Even registering a work is not mandatory, though registration is recommended as is it necessary to enforce exclusive rights of copyright through litigation.

Copyright provides the owner of copyright with exclusive rights to: 

• Reproduction
• Distribution
• Derivatives
• Public performance
• Public display

Copyright owners also have the right to authorize others to exercise the above rights, subject to certain statutory limitations. 

Who is the copyright owner of a work? 

• Generally, the copyright owner of a work is the author or authors who created that work. 
• There are some exceptions to the above guideline- including the Work for hire exemption. When a work is created by an employee as part of the employee's regular duties or when an individual and a hiring party enter into an express written agreement that a work is made for hire, then the party who hired the individual rather than the individual/author may be considered the copyright owner. 
• Copyright owners may also transfer their rights to another individual or party. 

The above information is based on:

Copyright Law of the United States and Related Laws Contained in Title 17 of the United States Code – June 2020: This publication contains the text of Title 17 of the United States Code, including all amendments enacted by Congress through March 27, 2020. It includes the Copyright Act of 1976 and all subsequent amendments to copyright law; the Semiconductor Chip Protection Act of 1984, as amended; and the Vessel Hull Design Protection Act, as amended. 

U.S. Copyright Office - Circular 1 Copyright Basics: A 10 page circular issued by the United States Copyright Office. It provides an overview of basic facts about U.S. copyright and copyright registration. It includes sections on: (1) Works eligible for protection, (2) Rights of copyright owners, (3) Who can claim copyright, and (4) Duration of copyright.  

We also recommend University of Texas Libraries Copyright Crash Course for learning copyright basics. As they state on their site, it "was originally created with faculty in mind, but can be used by anyone who is interested in understanding and managing their copyrights."