copyright and Japanese comic books
There's a large and growing market in Japan for comic books based upon characters created by others. While it's possible that the original creators might successfully bring copyright infringement suits against the creators of these works, such suits have been very rare. Maybe that's partly because the industry is benefitting tremendously from the existence of these books.
A Red Herring article penned by Larry Lessig takes a look at this phenomena. See Copy cats and robotic dogs: What lawyers can learn from comic books.. The focus of the article is upon a paper written by Temple Law professor Salil Mehra, which looks at the practice from a business perspective.
The article Copyright and Comics in Japan: Does Law Explain Why All the Cartoons My Kid Watches are Japanese Imports? will be appearing in the Rutgers Law Review and is available online here. If you're interested in copyright, fair use, artistic creation, and the business aspects of creative works, it's definitely worth the time reading Professor Mehra's article. And, while there are a lot of footnotes that you might be tempted to skip over, there are some great lines amongst them.