Can you use the name of a fictional character in someone else's book in the title of your own book?

Example: The key character in the book is named Robert Smith. He is tall, blonde, charismatic, and an FBI agent in Washington, D.C.. Hypothetical: You call your book "I Killed Robert Smith." Your Robert Smith is a small man with one leg who works as a postal worker in Tulsa, OK. If the book you took the character from is not part of a series, not famous, and the character is not itself famous in some protectable way -- AND your "Robert Smith" is a different character entirely, then you should be fine. Just don't try calling your book "I Killed Harry Potter."

Great question. See this 2009 Connecticut Law Review article by KATHRYN M. FOLEY entitled "PROTECTING FICTIONAL CHARACTERS: DEFINING THE ELUSIVE TRADEMARK-COPYRIGHT DIVIDE" Fictional characters are often entitled to copyright protection, and sometimes the protection can extend even further to trademark protection. Probably, if you are commercially benefiting from using the fictional character in the title of your book and the copyright has not expired, then you will liable for copyright infringement, as this is unlikely to fall under the "fair use" doctrine. And, of course, you are only going to benefit commercially if the fictional character is significant enough for the public to recognize. The answer to your question may depend on the facts concerning the fictional character and your book. Fictional character are not automatically protected and the law is unsettled. Sometimes, a fictional character may be consider just a stock character. The court may consider as a preliminary issue whether the fictional character is a proper subject for copyright protection. In this case, you state that the character is a "key" character. So you probably cannot use the character, but you do raise even more questions since you have said that the book is not related to the character. Definitely consult with an IP attorney if you are uncertain before publishing your book.

Generally, neither character names nor book titles are copyrightable. The only possible issue you might have is if the other book is part of a trademarked series and your use of the main character's name confuses consumers into thinking that your book is affiliated with that trademarked series.