Harper Lee Sues Hometown Museum for Exploiting ‘To Kill a Mockingbird’:

“Historical facts belong to the world,” notes the lawsuit, “but fiction and trademarks are protected by law.”

True.  Always ask for permission, first.  Titles can be trademarked – and that means you cannot freely use them for your own commercial ends.  Celebrities have a right to protect and limit the use of their names, too.  Always consult an attorney.