A copyright gives the owner the exclusive right to reproduce, distribute, perform, display, or license his work. See § 106 of the act. The owner also receives the exclusive right to produce or license derivatives of his or her work. See § 201(d) of the act. Limited exceptions to this exclusivity exist for types of "fair use", such as book reviews. See § 107 of the act. To be covered by copyright a work must be original and in a concrete "medium of expression." See § 102 of the act. Under current law, works are covered whether or not a copyright notice is attached and whether or not the work is registered.
http://www.law.cornell.edu/topics/copyright.html