It is not the sort of fair contest that would have been approved by one of the benign masters of Hogwarts. On one side is J K Rowling, one of the world's richest authors, in alliance with Warner Brothers, the mighty Hollywood film studio. On the other: a small Michigan-based publisher and a school librarian.
Ms Rowling argued in a Manhattan courtroom yesterday that the publication of Steven Vander Ark's The Harry Potter Lexicon by RDR Books is an infringement of her copyright.
There is something a little distasteful about this legal action. There is the fact that the book is a print version of a Harry Potter fan website which Ms Rowling herself endorsed only four years ago, calling it "my natural home".
Then there is the point made by another renowned fantasy storyteller, Terry Pratchett, to this newspaper's Pandora column last month:
"In fantasy writing, accusations of copying are very difficult to make. You know, who invented wizards? Who invented goblins? If we were going to start paying royalties for nicking one another's idea, we'd all have given our life savings to the Tolkien family a long time ago."
Ms Rowling has undeniably done a great service to children's literature though her Harry Potter books. But, for the sake of her reputation, it would perhaps be sensible for her to be a little less zealous about maximising the earning value of her boy wizard's "brand".
As they might say at Hogwarts, it's just not Quidditch.