Orphan works are copyrighted creative works like books, music, films, etc. whose owners cannot be located. Works can become orphaned for reasons such as the owner not registering the copyright, the owner selling rights without registering the transfer, or the owner passing away without heirs being found. Four factors are used to determine fair use: the purpose of the use, the nature of the work being used, the amount of the work being used, and the effect of the use on the market for the original or permissions. A checklist can help ensure uses adhere to standards of fair use and copyright.