By Adam Shaw

Children eager for the new Harry Potter

The fifth Harry Potter book - Harry Potter and the Order of the Phoenix - is published at midnight on Friday.

The books publisher's Bloomsbury have had a tremendous time of it all.

Their shares have risen by 22% this year while the market average has dropped by over 10%.

The price has risen so much that they are now considering splitting the shares by four to make them more easily tradable.

Stolen books

But the book itself is only part of the PR madness which has driven its success.

PRICE OF BOOK List price �16.99 Waterstone's �11.99 WH Smith �11.99 Amazon �11.24 Sainsbury �9.99 Tesco �9.97 Safeway �8.49

There have been accusations of book thefts.

Retailers must be hoping for a halo effect in which the massive sales of the new Potter book, help boost sales of other titles as customers come in to buy one book and walk out with a bag of others.

"I think more people are coming into the bookshops...It does help with the kids sales as the kids are getting more into reading, " says Becky Stradwick, a deputy manager at Books ect.

But the Harry Potter publication is very unusual.

Success not guaranteed

Around 3,500 books are published every month in the UK.

And the vast majority of them go unnoticed.

Most of them don't sell much and the authors remain poor and unknown.

The average salary of an author who is published is around �16,000 a year, according to the Society of Authors.

Thousands of people want to be published authors but never make it.

Stephanie Jackson is a non-fiction publisher with Dorling Kindersley.

She gets 6-700 book proposals a year.

Most are ill-prepared and directed at the wrong type of publisher, she says.

But if a book does make it to the shops - this is how the money works.

Profit margins

"Publishers sell into... bookstores at 50% discount so you can use that as a rough guide," she says.

That means if a book costs �20 - the publisher gets �10.

As a publisher I am very happy if I can get an 8% return on my investment Stephanie Jackson

From that �10 they pay the author who usually gets between 8-10% of that figure.

They also have to pay for the cost of originating the book, which includes paying editors their wages, and footing the bill for the cost of illustrations and for advertising.

"As a publisher I am very happy if I can get an 8% return on my investment... it probably takes me a year to recover that investment," says Stephanie.

The good thing about Harry Potter as far as budding authors are concerned is that it shows not only can unknown authors make it very big.