Copyright creates a monopoly in the usage of a literary work for a limited term of years. After the copyright is expired, the literary work enters the public domain. This means the rights granted during the term of the copyright are no longer exclusive, and the book may be freely used by anyone. For example, if a work is in the public domain, anyone may republish the book and sell it commercially or write a sequel to the book using the same characters as the original.
Books created after Jan. 1, 1978, regardless of whether they’ve been published, are protected by copyright for the life of the author plus 70 years. Some books that are works-for-hire, i.e., created in the scope of employment, or that are created anonymously or pseudonymously are protected for 95 years from the date the work was created or 120 years from the date it was published, whichever is shorter. The law on copyright duration has been amended many times and determining whether an older book is still protected by copyright is more difficult. However, any book published prior to 1923 is currently in the public domain. Works published prior to Mar. 1, 1989, without any notice of copyright are also in the public domain, because the law required notice on all works published before that date.
Even if an out-of-print book is still protected by copyright, some uses of that book may be considered fair use. Fair use is a statutory exemption that allows for works to be used for criticism, scholarship and other reasons that promote the public good. For example, copying several chapters of an out-of-print book for a non-profit educational purpose would probably be considered fair use.However, fair use arises as a defense in a copyright infringement lawsuit, and the U.S. Copyright Office warns against using fair use as a substitute for obtaining permission to use a work.
If an out-of-print book includes a copyright notice, the notice will list the name of the author or copyright holder. U.S. Copyright Office records are open to the public to search for copyright holders as well, if the book does not include a notice. The Copyright Office will also conduct an official search into the copyright status of a work for a fee. There are also organizations, such as the Copyright Clearance Center, that serve as clearing houses to obtain permissions and licenses on behalf of individuals who wish to use copyrighted works.