Copyright is a set of rights provided by the U.S. Constitution "to promote the Progress of Science and useful Arts, by securing for limited Times to Authors and Inventors the exclusive Right to their respective writing and Discoveries" (Article 1, Section 8 of the U.S. Constitution).
Copyright is a type of intellectual property protection given by the laws of the United States (title 17, U.S. Code) that protects "original works of authorship" as soon as an author "fixes the work in a tangible form of expression." This means as soon as a creator produces their work copyright is automatically applied. Original works of authorship encompasses a lot of different types of works, including literary, dramatic, musical, artistic, and more!
Copyright takes effect immediately and does not require registration. Under the United States law, copyright lasts for 70 years after the death of the creator, or in the case of works for hire and anonymous/pseudonymous works, 95 years from publication or 120 years from creation, whichever is shorter.
Copyright provides the creator the following exclusive rights:
Copyright can be transferred in part or all to another person or entity (like a publisher) with written consent.
Some exceptions do apply, like fair use. If a person uses copyrighted material, where exceptions do not apply and without permission from the author, the user could be held liable for copyright infringement.
What works does copyright protect?
Musical works, including accompanying words
Dramatic works, including accompanying music
Pantomimes and choreographic works
Pictorial, graphic, and sculptural works
Motion pictures and other audiovisual works
Adapted from U.S. Copyright Office Circular 1, Copyright Basics.
What is NOT protected by copyright?
Ideas, procedures, methods, systems, processes, concepts, principles, discoveries, or devices, as distinguished from a description, explanation, or illustration
Titles, names, short phrases, and slogans; familiar symbols or designs, mere variations of typographic ornamentation, lettering, mere listings of ingredients or contents
Works that are not fixed in a tangible form (such as an improvised performance that is not recorded)
Works produced by the U.S. Government
Works consisting entirely of information that is common property and containing no original authorship
Works in the public domain
Adapted from U.S. Copyright Office Circular 33, Works Not Protected by Copyright.