JK Rowling said: "I am very frustrated that a former fan has tried to co-opt my work for financial gain," however, legal representatives for RDR Books said the plan was a "legitimate literary activity".
JK Rowling says she intends to write her own definitive Harry Potter encyclopaedia, and to include material in it that was not in the books.
Referring to Steve Vander Ark’s book, JK Rowling said: "Both I, as the creator of this world, and fans of Harry Potter would be exploited by its publication. I feel intensely protective, firstly of the literary world I spent so long creating, and secondly, of the fans who bought my books in such large numbers."
The Harry Potter Lexicon draws on material from an Internet fan website of the same name, and RDR Books state on their site that they are "determined to publish this book for the benefit of Harry Potter fans everywhere."
RDR Books had agreed to delay the publication of the Harry Potter Lexicon after JK Rowling sought an injunction against it back in October when the book was due to be published on 28 November 2007 but now they say they plan to publish.
