May I write a novel based on another novel?
<p>Like if I want to write a book series about <em>Harry Potter</em> character Rita Skeeter's life, may I do it? I always hear that this isn't allowed. But as far as I know some people have written a book about what happened after Potter won the war. And the series "män som hatar kvinnor" has a fourth book called "Det som inte dödar oss".</p>

<p>So is it allowed to write a book (and make money with it), if you base the plot and/or the characters on something written in another book?</p>

<p>Presumably you are referring to works commonly called "fan fiction."  Under copyright law these <em>might</em> be considered "derivative works" and therefore subject to the rights of the copyright owner.  However, they <em>might</em> also qualify for exemption from copyright enforcement under "fair use."</p>

<p>It appears that the legality of fan fiction is not settled law, and the outcome of legal challenges have turned on facts specific to each case.  Decent background on the question is <a href="https://en.wikipedia.org/wiki/Legal_issues_with_fan_fiction" rel="nofollow">summarized on wikipedia</a>.</p>

<p>A recent case explored a new book written by Fredrik Colting a Swedish writer, which used the name and characterization of Holden Caulfield, the main character of <em>Catcher In The Rye</em>.  The book was ruled to be derivative and the court issued an injunction preventing it from being marketed or sold in the USA. <a href="http://www.nytimes.com/2009/07/02/books/02salinger.html?_r=0" rel="nofollow">http://www.nytimes.com/2009/07/02/books/02salinger.html?_r=0</a></p>

copyright fair-use