Doodle-covered exercise books that belonged to a schoolboy Sir Terry Pratchett have come to light and reveal he already had many ideas for his early stories.

They provide a fascinating, rare insight into the legendary late author's creative process as he allowed his mind to drift during lessons at secondary school.

Pratchett, who died following an eight year battle with Alzheimer's Disease in 2015, was fiercely protective of his unpublished stories.

Doodle-covered exercise books that belonged to a schoolboy Sir Terry Pratchett have come to light and reveal ideas for his early stories

The much-loved writer requested before his death that his hard drive containing incomplete works was crushed with a steam roller.

His wish was carried out to much fanfare at the Great Dorset Steam Fair last August.

The exercise books date from 1962 to 1964, when Pratchett was entering his teenage years as a pupil at High Wycombe Technical School, now John Hampden School, in Buckinghamshire.

On first impression the pages appear to be covered in random doodles, but upon closer inspection it is possible to find numerous references to Pratchett's early works.

A drawing of 'snargs', the carnivious creatures which feature in the novel The Carpet People

Skecthes that resemble Pratchett's carpet people. The doodles provide a fascinating, rare insight into the legendary late author's creative process as he allowed his mind to drift during lessons at secondary school

His maths exercise book features drawings of figures which closely resemble Pratchett's own illustrations for his first novel 'The Carpet People' which was published almost a decade later in 1971.

There is a drawing of 'snargs', the carnivious creatures which feature in the novel, interspersed with sketches of spaceship battles, astronauts and aliens.

About this time, Pratchett developed an interest in Sci-fi and began attending conventions.

His German exercise book has the following joke written on the inside cover: 'Do you smoke? No, but I burst into flame occasionally.'

Pratchett's old exercise book for english and maths, heavily covered in doodles

His economic history exercise book contains an early draft of his fifth published story 'The Solution' which appeared in the school's magazine, Technical Cygnet, in July 1964.

In the story, an inspector named Gustave sneaks on board a plane piloted by a man named John Pyecraft, suspecting him of being a smuggler.

He tells Pyecraft he knows he has been smuggling something on board the old planes but he doesn't know what.

While he is talking Pyecraft attacks him and in the chaos the plane crashes.

Several calligraphic attempts at 'The Carpet People, left, and a quick self-portrait, right

The two men huddle together for warmth on the side of the mountain in front of the remains of the crashed plane.

The inspector turns to Pyecraft and says 'you might as well tell me now what you were smuggling'.

Pyecraft looks at him sadly and replies: 'Aircraft'.

The sale also includes his sketch pad containing a drawing which may be a self portrait and several practice attempts at doing calligraphic writing for 'The Carpet People'.

The items have been consigned to auction by an anonymous vendor who was personally given them by Pratchett in the 1980s.

A Pratchett skecth titled 'On the pelmet'. The items have been consigned to auction by an anonymous vendor who was personally given them by Pratchett in the 1980s

The collection, which consists of four exercise books and a sketch pad, is tipped to sell for £8,000.

Max Hasler, specialist at Forum Auctions, of London, who are selling the archive, said: 'This is a superb archive that gives an insight into the early imaginative workings of the young author.

'Manuscript material by Pratchett is rare and I'm not aware of any other other examples of anything like this coming on to market.

'He was fiercely protective of his unpublished work and it was his wish that a steam roller crush his hard drive so no one would be able to see his incomplete stories.

'The exercise books date from around 1962, when Pratchett was aged around 13 or 14, attending the High Wycombe Technical School.

A science-fiction alien spaceship sketch. The collection, which consists of four exercise books and a sketch pad, is tipped to sell for £8,000

'Even when not directly related to later published works the drawings and fragments display Pratchett's characteristic wit and humour as well as a fascination with comics, Heath-Robinson like inventions and the creation of bizarre and intriguing fantasy worlds.

'It is really exciting to get a glimpse into his very early stage as a writer and to see his imagination pour out on to the pages.'

Pratchett has sold more than 85 million books and is best known for his Discworld series of 41 novels.

His first Discworld novel, 'The Colour of Magic', was published in 1983, after which he wrote on average two books a year.

His final Discworld novel, 'The Shepherd's Crown', was published in August 2015, five months after his death aged 66.

In 2007, Pratchett announced that he had been diagnosed with early-onset Alzheimer's disease.

He became a campaigner and patron for Alzheimer's Research UK. He was knighted for services to literature in the 2009 New Year Honours.

The auction takes place on May 31.