Nov. 20 (Bloomberg) -- Sotheby's is betting Harry Potter's fame will lift a handwritten fairy tale by J.K. Rowling to a record 50,000 pounds ($103,000) at a Dec. 13 London charity auction.

``The Tales of Beedle the Bard'' went on show today at the auction house, with a valuation similar to a 1902 edition of Beatrix Potter's ``The Tale of Peter Rabbit.'' The success of the Harry Potter books, which have sold more than 350 million copies, will spill over onto Rowling's latest work, Sotheby's said.

``J.K. Rowling's commercial success adds value to the manuscript,'' Sotheby's book specialist Philip Errington said in an interview. ``It makes it more desirable.''

Living authors' unpublished manuscripts are rarely sold at auction, so they're hard to value. A computer printout of a novel by U.K. mystery writer Ruth Rendell sold for about 2,500 pounds in July, Sotheby's said. Rowling's work is illustrated with ink drawings.

Items directly related to the Harry Potter character fetch premium prices. Sotheby's sold a postcard with a brief plot summary in Rowling's hand of ``Harry Potter and the Order of the Phoenix'' for 28,680 pounds in 2002. A signed copy of ``Harry Potter and the Philosopher's Stone'' sold for 27,370 pounds in May at London's Bloomsbury Auctions, setting a record for a Potter novel.

Alice, Winnie

Dead authors' manuscripts and books can fetch much more. An 1886 copy of Lewis Carroll's manuscript ``Alice's Adventures Under Ground,'' later reworked as ``Alice's Adventures in Wonderland,'' took 157,250 pounds at Sotheby's in 2001, and a 1926 edition of A.A. Milne's ``Winnie-the-Pooh'' went for 100,150 pounds in 2002.

Christie's International sold the 1902 inscribed edition of Beatrix Potter's ``The Tale of Peter Rabbit'' for 47,800 pounds in 2004.

``The Tales of Beedle the Bard,'' leather bound with silver mounts, is one seven copies made by Rowling, who gave the other six to people associated with the success of the Potter series, Rowling said in an introduction to Sotheby's catalog. The copy on show at Sotheby's will be sold to benefit the Children's Voice, a charity co-founded by Rowling and Emma Nicholson, a member of the U.K. House of Lords.

The estimated range is 30,000 pounds to 50,000 pounds.

The other six copies of the fairy tale may come onto the market ``at some point, but this is the first,'' Errington said.

Billionaire Rowling, 42, has said she'll produce no more Potter books. Writing the fairy tale was a ``way to say goodbye to a world I have loved and lived for 17 years,'' Rowling said in the Sotheby's catalog.

Rowling's latest Potter book, ``Harry Potter and the Deathly Hallows,'' sold 8.3 million copies in its first 24 hours and 11.5 million in its first 10 days. There are 140 million copies of the Harry Potter books in print in the U.S. alone.

Sotheby's, the world's second-largest auction house, has its main salerooms in New York.

To contact the reporter on this story: Linda Sandler in London at lsandler@bloomberg.net.

Last Updated: November 20, 2007 10:25 EST