By Bill Wilson
BBC News Online business reporter
A rare copy of Canterbury Tales
They fill shelves in homes everywhere, but many people may not be aware their books could be a potential goldmine. BBC News Online looks at book collecting in the latest in its series on fun investments.
The popularity of auction and collecting programmes on television has made everyone aware that there may be unrealised assets in everyone's homes.
And the recent success of the Harry Potter and Lord of the Rings films have boosted the prices of the books on which they were based, making bibliophiles everywhere wonder if they have a rarity among their collection.
Clive Farahar, of bookdealers Farahardupre, has featured on the BBC's Antiques Roadshow programme.
He said: "There has been a great increase in book collecting in recent years.
"Members of the public are realising that the books on their shelves might be valuable."
As part of the boom, a set of Harry Potter first editions can now sell for at least £25,000.
Twenty years ago a set of the three Lord of Rings volumes, published in the mid-1950s, were selling for between £800 and £1,000. Now a set goes for between £17,000 and £25,000.
Mr Farahar said: "There has been a rise in "trophy-collecting", where people want to be to say they have a complete set of Harry Potter books.
"You would probably not want to even open those books in case you cracked the spine.
"What is wrong with something like Tolkien, is that the price has been going up far too fast, it could plummet again in the same way after rising so quickly."
So what should the new collector of modest means, looking to perhaps make a profit from his or her hobby, look to buy?
"People should initially buy books because they are interested in the subject matter, not necessarily because they think they are going to make a fortune out of it.
"Buy books that you like, that you can relate to, then if it does not make a great price in later years at least you will have a book that you still want to own."
He added: "Children's books are always well-worth collecting, and are a popular subject among book buyers.
"I would suggest something like pop-up books are worth buying.
"They are available for only a few pounds in remaindered book shops, yet very few will remain in good condition in years to come after children have had their hands on them.
"This could turn out to be a good investment years down the line."
It may come as a surprise to bookworms but rare volumes are not necessarily the ones that fetch the most money.
Mr Farahar said: "Rarity does not necessarily make a book marketable. Something that is fairly common can still fetch a higher price.
"Growth areas are modern first editions and 19th century travel books, yet there are much rarer books than them.
"But when there are a lot of a desirable book people can compare different copies in different condition, with collectors trying to find a copy in the best-possible condition.
COLLECTING POINTS TO REMEMBER
Buy books you are interested in
Buy in as good condition as possible
Modern first editions should remain unread if possible
Try to buy from a reputable dealer
Rare does not necessarily mean desirable
"You go back to the 17th and 18th centuries, the books are much rarer, but the markets for them are much more stable and not subject to sudden crazes - which is not necessarily a bad thing."
Other stable markets over the years have been in works by favourites such as Graham Greene and Ian Fleming.
He said: "Graham Greene is very good, and Ian Fleming has been very stable over the past 30 years - he has been fetching very high prices for the Bond books, and growth has remained fairly stable."
So, once you decide what to collect, where should you look to buy?
He said: "The internet is slightly unregulated, however, it is a very useful tool for checking current prices."
One online marketplace is ABE, where buyers can search from titles for sale by dealers from around the world.
Other internet sites of use are those of the UK-based Independent Booksellers' Network, and UKBookworld.com, which also allow potential buyers the chance to search dealers' stock lists.
This Harry Potter first edition sold for £13,500 at auction in 2003
There are also auctions held by the major names such as Sotheby's and Bonhams, but items turning up in these houses are likely to be beyond the pocket of the new collector.
However, most towns and cities in the country have auction houses and these are worth checking for sales of books.
Gems can also turn up in charity shops, car-boot sales, and organised book fairs, and journal Book and Magazine Collector carries book advertising and articles.
But Mr Farahar: "It is always best to deal with your established friendly bookdealer.
"It is very important to deal with people who are well-known, and members of a trade organisation."
Major bodies in the UK include the Antiquarian Booksellers Association (ABA) UK, and the Provincial Booksellers' Fairs Association (PBFA).
'Hard to predict'
Condition is extremely important, and Mr Farahar advises: "With all modern firsts, they need to be in as fine a condition as possible.
"The price-corner of the paper dust jacket should still be unclipped, there should be no written dedications inside, and the book and dust wrapper not worn.
"Bear in mind that if you going to buy a modern first, you do not have to read it - wait until the book comes out in paperback or borrow a copy from your library."
He concludes: "There is a pleasure in books, and people are inevitably drawn to books.
"Prices can soar for a number of reasons, such as with Tolkien and the Lord of the Rings film, but it is an impossible market to predict.
"Remember there are pitfalls, and like shares or any other type of investing, the value of your purchase might go down as well as up."
The opinions expressed are those of the author and are not held by the BBC unless specifically stated. The material is for general information only and does not constitute investment, tax, legal or other form of advice. You should not rely on this information to make (or refrain from making) any decisions. Always obtain independent, professional advice for your own particular situation.