JK Rowling said all writers would be 'endangered'
JK Rowling has told a New York court that publication of an unofficial Harry Potter encyclopaedia could "open the floodgates" for countless rip-offs.
All writers would be threatened by the move. she said on the final day of a three-day hearing.
Ms Rowling, 42, is taking legal action against Steve Vander Ark and his publisher RDR Books over plans to release a Harry Potter encyclopaedia.
"This case is about an author's right to protect their creation," she said.
"If this book is allowed to be published the floodgates will open," she added.
"Are we, or are we not, the owners of our own work? It's not just my work that is endangered."
Ms Rowling, who was testifying for the second time, called Mr Vander Ark's book, The Harry Potter Lexicon, a "sloppy, lazy" work, unlike other Harry Potter companion books already published.
Mr Vander Ark, a 50-year-old former school librarian, compiled the guide from material on his long-running website.
RDR Books has argued that it is little different than any other novel reference guide and should be allowed to go to press without interference.
Ms Rowling said she was "vehemently anti-censorship" and generally supportive of the right of other authors to write books about her novels, but said Mr Vander Ark had merely reprinted it in an A-to-Z format.
In a statement released after Wednesday's hearing, Ms Rowling said Mr Vander Ark's book had "overstepped" the mark.
"The book at the heart of this case has overstepped a boundary so unreasonably that I have been forced, regretfully, to take legal action," she said.
"Authors have a right to protect their works from misuse. Do I have fewer rights because many people read my books?
"If this book is published, it will open the floodgates for anyone to lift an author's work and present it as their own. But if it is not published, that will be a boon not only to all who create original works, but to all who enjoy those works."
US District Judge Robert Patterson Jr, who has urged the two sides to settle out of court, will decide whether to grant Ms Rowling's request to block publication of the guide to the characters, places and spells in her novels.
He said the case involved unresolved areas of American law and was almost certain to end in years of appeals.
"I think this case, with imagination, could be settled," the judge said.
He is not expected to announce his decision for several weeks.