Filed at 2:12 p.m. ET

NEW YORK (Reuters) - Well into the electronic age, prices of rare manuscripts and books are skyrocketing as collectors seek to literally hold on to the written word.

Rare, however, need not mean ancient or even vintage. Harry Potter books are worth up to $10,000, if it is the hard-to-find 1998 first British edition of ``Harry Potter and the Philosopher's Stone,'' in mint condition.

``Book prices have been going up consistently,maybe not the stratospheric prices of the art market,'' said Francis Wahlgren, head of printed books and manuscripts at Christie's New York (http://www.christies.com).

``Certain authors have begun to jump in price in the last five years. The high spots of literature and science are becoming more and more in demand, the real classic names -- Hemingway, Fitzgerald, Kerouac, books we grew up with in school.''

At Christie's this month, a 1922 first edition of James Joyce's ``Ulysses'' sold for $460,500 -- the highest price paid at auction for any work of 20th century fiction. It was one of 100 copies printed on Dutch handmade paper, and was inscribed to Henry Kaeser, the publisher.

World auction records were also smashed for first editions of authors Vladimir Nabokov, Jack Kerouac, F. Scott Fitzgerald, Frank L. Baum and J.R.R. Tolkien. A private American collector paid $273,500 for a 1955 copy of Nabokov's ``Lolita,'' with the author's inscription to Graham Greene. And a 1957 presentation copy of ``On The Road,'' that Kerouac inscribed to his lover, Joyce Johnson, sold for $185,500.

``They've proven to be great investments, even though that's not necessarily why they were purchased,'' said Natalie Bauman of Bauman Rare Books (http://www.baumanrarebooks.com), one of the largest U.S. dealers, with two stores in New York and one in Philadelphia.

Many books have quadrupled in value over the last six or seven years, she said, and her customers often thank her for selling them books that have made up for losses in the stock market.

Prices are highest for books that ``made everything after that different,'' in the way we look at the world, in any language or field, Bauman said.

Children's book prices have escalated, and those illustrated by famous artists, or have extraordinary color plates such as ornithologist John James Audobon's bird prints, are highly desirable. Some books like atlases are works of art themselves, with handmade paper and beautiful binding.

``The more significant the text in the cannon of a particular writer, as a function of its place in the narrative of contemporary literature, the more powerful the response of the market,'' said Glenn Horowitz, a New York dealer who bought the ``Ulysses'' copy last week on behalf of a client.

First editions are always the most valuable, especially if few copies were printed and if inscribed by the author.

Expect to pay about $100,000 for one of 1,250 first-edition copies of Charles Darwin's ``Origin of the Species,'' printed in 1858. It cost just $30,000 10 years ago.

Hemingway's ``Old Man in the Sea,'' worth $700 in 1992, now sells for up to $3,000. If inscribed by him, the price is closer to $20,000, Bauman estimated.

As with stamps, misprints are far costlier than the corrected versions. The first printing of Hemingway's ``The Sun Also Rises'' had a typo that has boosted its price up to $75,000, versus $10,000 for the corrected first edition, Bauman said.

While prices at the high end have escalated, the lower-end market has evened out, thanks to the Internet.

``There aren't as many $50 or $100 books sold for $10 because a dealer immediately goes online to compare prices,'' said Forrest Proper, owner of Joslin Hall Rare Books (http://www.joslinhall.com). ``On the other hand, for scarcer material, prices have gone up because you no longer have to guess whether something is scarce or not.''

Dealers worldwide post on the database of the Antiquarian Booksellers Association of America (http://abaa.org), helping to create a common market.

Buying online, however, has its pitfalls. Forgeries aside, many sellers may inaccurately describe books or assume they have a first edition when they don't (books did not say ``First Edition'' until the 20th century).

In any case, make sure you buy from a reputable seller and have recourse if the product falls short of its claims, experts said.

(This column appears every other week. E-mail any comments to richard.chang(at)reuters.com).