Know why some copies sell for a few hundred euros and some for hundreds of thousands before embarking on that epic purchase, writes Michael Parsons.

Forget the villa on the Algarve, the apartment in Budapest or the converted barn in west Cork. Consider instead buying one of the few available copies of Ireland's most famous, controversial and valuable book. Not him again. Please. Had enough of James Joyce to last a lifetime? Ulysses hasn't gone away you know.

Apart altogether from its literary merit, surviving copies of the genuine first edition have become red-hot investment options. It is already the most expensive book published in the 20th Century and the fuss of centenary Bloomsday will serve to drive demand ever higher.

A word of caution. Huge sums of money can be at stake regarding the official definition of "first edition". It is crucial to understanding why some copies change hands for a few hundred euros and others for hundreds of thousands.

In publishing, the first edition of a book means its first publication in a particular format. When, for example, a new novel is published in hardback it may be reprinted five times. Each printing is technically part of the first edition. If the book then appears in paperback, this would be referred to as the second edition. To collectors of rare books, "first edition" means the first printing of the first edition.

Ulysses was published in Paris on Joyce's birthday, February 2nd, 1922. One thousand numbered copies were printed in Dijon by a firm called Darantiere in three batches. One hundred were printed on Dutch handmade paper and each signed by Joyce; 150 on vergé d'Arches paper and 750 on vergé à barbes paper.

They were clad in soft covers, which featured the title and author's name in white on a blue background. The book contains this printed statement: "The publisher asks the reader's indulgence for typographical errors unavoidable in the exceptional circumstances."

The prices in 1922 were: 350 French francs each for the signed copies; 250 francs for the vergé d'Arches copies and 150 francs for the remaining 750. These 1,000 books are the true blue "first editions" of Ulysses.

The first two copies delivered from the printers were numbers 901 and 902, which arrived in Paris by train. Joyce presented the first to his wife Nora and the second went to Sylvia Beach who put it on display in the window of her left-bank bookshop, Shakespeare and Company, which published the book. Nora's copy appears to have been lost. Number 902 is today in a university library in Buffalo, New York.

What about the other 998? Laura Barnes-Weldon, national co-ordinator of the ReJoyce festival believes that about 800 copies have survived. Of these half are in "public" collections. It is reasonable to assume that these copies will never be sold. Around 200 copies are reliably believed to be lost or destroyed.

This means some 400 copies exist in private ownership, which is where they tend to stay. On the few occasions when they are offered for sale they usually end up being handled by rare book experts at two of the world's leading auction houses, Christie's and Sotheby's.

In general, signed copies are the most desirable. Copies that are inscribed by Joyce to family, friends. publishers or admirers are more valued than those with a mere signature. Overall condition will also affect price and few copies have survived with the original wrappers intact.

The highest price achieved to date was for one of the 100 signed copies inscribed to Henry Kaeser, a Swiss publisher, and sold by Christie's, New York in 2002 to a private collector for $460,500 (377,5000). This copy is not actually numbered, which adds to its mystique.The buyer was a private collector.

Other notable prices include $288,000 for number 95 sold by Sotheby's New York in April this year and $119,500 for number 282 sold by Christie's in 1992. These were also purchased by private collectors.

So are there any for sale today and where are they? If you want to buy a copy, the best sources are specialist auctions and book dealers. Good quality inscribed copies are extremely rare. According to Peter Selley of Sotheby's: "One of the most important copies ever to come to market is number 308 which will be auctioned at Sotheby's on July 8th in London. It was presented by Joyce to his brother Stanislaus and carries the inscription: 'To Stannie Jim Paris 11 February 1922.' The estimate is 119,000 to 149,000."

This seems to be very conservative. Private collectors regard Ulysses as an essential component of any library of great works of literature. So expect fierce competition among bidders. Rumours are circulating that a number of Ireland's "new rich" will battle with international collectors to acquire this rare example of one of the State's most revered cultural icons.

Also in the Sotheby's sale is an unsigned copy - number 910 - estimated at 10,400, which illustrates the huge variation in prices.

There are three copies for sale at Cathach Books in Dublin. Offers "in excess of 100,000" are invited for a signed copy. The others are priced at €60,000 and 22,500 respectively.

A few unsigned copies are currently on sale at antiquarian bookshops in London and the US. Most have been "restored" to varying degrees, which explains the price range of 5,000-50,000. Before buying one, it would probably be a good idea to undertake further research.

Other than the original 1,000 there are other copies of Ulysses worth considering. Shakespeare and Company re-printed the book many times and prices fall dramatically with each of the later printings. For example, a copy of the fifth printing is on sale at Cathach Books for €750.

There are several other editions and many are valuable and highly collectable in their own right. They include the first "British" edition of 2,000 numbered copies, published later in 1922 by the Egoist Press, which for legal reasons was printed in France. There's one currently for sale at 2,800. The first edition actually printed in England was published in 1936 by Bodley Head. One thousand copies were printed, 100 of which were signed by Joyce. Prices range from €2,700 for an unsigned copy to as high as €40,000.

A copy of the first American edition by Random House in New York, 1934 would fetch about 3,500. But an unofficial pirated version had already been printed in Manhattan in 1929. Most were seized and destroyed by the Society for the Suppression of Vice, but a scarce copy retails in the region of 13,500.

Art lovers may prefer the 1935 New York Limited Editions Club version illustrated by Matisse, who signed 1,500 copies, valued at about 5,000. Joyce signed 250 of these and a copy with both signatures sees the price quadruple.

There's a lucrative market in first editions of foreign language editions, with those in French and German especially attractive as Joyce spoke these languages and supervised the publication of both translations. A copy of the first German edition is at Cathach Books for just under 13,000.

The permutations it seems are as varied as Joyce's turns of phrase. Caveat emptor.