There are situations in which you do not have to obtain permission to reproduce copyrighted work. This rule is called “fair use” or has fallen into public domain. Fair use happens when a copyrighted work is used as a quote and is used as a comment or to criticize. For instance, quoting one or two lines from a song for a review, summarizing an article for a report or reference in a court case. Fair use is also used in what is called a Parody, which criticizes a work by imitating it in a funny way. Determining “fair use” is sometimes difficult because there are no clear rules only generalized rules in an attempt by lawmakers and judges not to limit it definition. “Fair use” is treated much like free speech, wanting it to be open to interpretation.