This researcher, and probably most people reading this Entry, missed a big opportunity in 1997. Harry Potter and the Philosopher's Stone was first published that year by Bloomsbury. If we'd had the foresight to buy it, we could be selling it now for approximately £10,000 - the price a first edition reached at a Sotheby's auction in 2002.

First edition books are nearly always far more valuable than later editions, but they aren't always easy to spot. Very old books are sometimes helpful enough to print 'First Edition' inside the cover, but modern publishers don't tend to do that. Fortunately, there are other ways of telling. This Entry will not, however, make you an expert on book appraisals. There are always exceptions, and you should consult an expert if you think that your book may be valuable.

What is a First Edition?

The first commercial print run of the book is the first edition, first printing. It's that simple. If for any reason there aren't enough books in that run, and another batch is printed, they will still be first edition books, but second printing - and nowhere near as collectable. It is widely accepted that 'first edition' is short for 'first edition, first printing' when buying or selling books (although, pedantically speaking, it shouldn't be).

The first edition continues until the book is changed. A new version of the book is then typeset, which becomes the second edition.

The Number Line

By far the most common (and arguably the most international) method of indicating modern first editions is the number line. No, not that row of numbers you learned to count on, but a row of numbers inside the cover.

First, you have to find the relevant page. It will be very near the front of the book, before the story starts but perhaps after the dedication or other miscellaneous pages. It's usually on the left-hand page, and in small print. It's got all the boring facts that people don't even glance at, such as the copyright notices and the conditions of sale. Found it? Good.

The number line is not the ISBN number. It's the other one, without ISBN in front of it. It may be long or short, and the numbers may be in any order or none. What's important is the lowest number in the line - that's the printing number. Therefore if the number line says 8 9 4 1 5 7 2 6 the number one in the line means you've probably got a first edition.

Astute readers may have detected a note of caution there. That's because some publishers, for reasons known only to themselves, make things more difficult. Named and shamed as an example are Random House. They sometimes start their first editions on number two - although they will then print 'First Edition' inside the cover, so remember to read the whole page carefully. Other publishers use letters instead of numbers, with A being 1, B representing 2, and so on. Some use the number line to refer to printings by that publisher only, in which case previous publishers should be listed inside the cover.

Other Ways of Spotting First Editions

Since the number line method wasn't widely used until the 1980s, you may well find books without one. Luckily, there are other ways of telling if your book is a first edition.

Before anything else you should check to see if the book has 'First Edition, First Printing' written inside the cover. If so, you've got pretty irrefutable evidence. If not, take a look at the dates in the book. If the date of first publication doesn't match that of your edition then you're out of luck. If it does match then it might be a first edition - but bear in mind that successful books will have more than one print run a year.

And then, of course, there's the trusty old Internet. Try searching for your book online, possibly with the words 'first edition' attached. You may well find the information that you need. In stubborn cases, identification may come down to a crucial error or tiny variation in cover design.

The Bottom Line

Does this make your book valuable?

Not necessarily. Only an expert can tell you what your book is worth, but the following factors are worth considering - although there are always exceptions:

• Condition - obviously, books in good condition are more valuable than their tatty counterparts. That doesn't mean that a battered book is worthless, just not as valuable as a pristine one.
• Rarity - if there are thousands of first editions in existence, they'll each be worth less than if there were a mere handful.
• Signed Editions - signatures of the author or the illustrator usually make the book more valuable.
• Hardback - a hardback book with a dust cover is more valuable than a paperback.
• Book Clubs - special prints for book clubs, libraries or the like aren't usually very sought after.
• Known Books - if people haven't heard of the book or the author they aren't likely to pay much for it.
• The Country - in nearly¹ every case a first edition from the country of original publication is by far the most collectable.

What's on your bookshelf?

It might be worth checking your bookshelf for the following...

• A first edition of The Hobbit, by JRR Tolkien, sold for £43,020² at Sotheby's in 2002.

• A first edition of The Canterbury Tales, by Geoffrey Chaucer, became the most expensive book ever sold when it made £4.6million at Christies in 1998 - but since there are only twelve copies known to exist the chances of you owning one are pretty slim.

• A first edition of Pride and Prejudice, by Jane Austen, sold for £40,000 in July 2002 at Lyon and Turnbull.

And now for one you might have a chance of finding in your collection:

• Bloomsbury Book Auctions sold a first edition of The Hitchhiker's Guide to the Galaxy, by Douglas Adams, for £300 in 2003.