Peter Jackson directed the first film

Mr Perry admits that he is "ceasing and desisting" until an agreement is worked out.

Wendy Strothman, an estate representative and executive vice president of Tolkien's US publisher, Houghton Mifflin, is not so sure.

She said his book "amounts to a retelling of The Lord of the Rings in a different form".

"That is not something the estate condones," she added. "I think if people want to read The Lord of the Rings, they should read the original."

Ms Strothman, whose publishing house is not involved in the suit, said the estate's decision to go to court was triggered by Mr Perry's refusal to provide a manuscript.

'Steal'

Mr Perry said he told the estate's lawyer, when they began corresponding last autumn, that he would turn over a copy if the firm would sign "a nondisclosure agreement", which it refused to do.

He said: "I didn't want somebody to steal my format."

In a letter last October to the estate's lawyers, Mr Perry admitted his book would have limited appeal.

He wrote: "To be honest, [the book] makes for dull reading.

"It isn't exciting and it isn't literary and it wasn't intended to be. It's like a dictionary, it packages facts about Rings in the most useful possible format."

Liv Tyler stars in the Lord of the Rings film

The estate's lawyers will review the work in its entirety and decide whether to press for a permanent ban on publication.

The first of the films of Tolkien's trilogy, The Fellowship of the Ring, is one of the biggest hits in worldwide cinemas and is expected to win several Oscar nominations.

The next two movies of the series will be released later this year and in 2003.