British fantasy author Terry Pratchett has died at the age of 66, eight years after being diagnosed with Alzheimer’s disease.

“The world has lost one of its brightest, sharpest minds,” said Larry Finlay of his publishers Transworld.

The creator of the Discworld comic fantasy book series died at home, surrounded by his family, “with his cat sleeping on his bed”, Larry Finlay has said.

Terry Pratchett wrote more than 70 books during his career and completed his final book last summer.

He “enriched the planet like few before him” and through Discworld satirised the world “with great skill, enormous humor and constant invention,” said Larry Finlay.

Terry Pratchett leaves wife Lyn and daughter Rhianna.

The announcement of Sir Terry Pratchett’s death was made on his Twitter account on March 12, with Rhianna later writing: “Many thanks for all the kind words about my dad. Those last few tweets were sent with shaking hands and tear-filled eyes.”

Despite campaigning for assisted suicide after his diagnosis, Sir Terry’s publishers said he did not take his own life.

The Discworld series – which started in 1983 – was based in a flat world perched on the backs of four elephants which, in turn, stand on the back of a giant turtle.

By 2013, Terry Pratchett had written more than 40 installments.

At the peak of his writing powers, Terry Pratchett – known for his striking dress sense and large black fedora – was publishing more than three books a year. His quirky and satirical view of the world won him a worldwide following.

At the turn of the century, Terry Pratchett was Britain’s second most-read author, beaten only by J.K. Rowling.

In August 2007, it was reported Terry Pratchett had suffered a stroke, but the following December he announced that he had been diagnosed with a very rare form of early-onset Alzheimer’s disease which, he said, “lay behind this year’s phantom stroke”.

Knighted in 2009, Terry Pratchett said: “It would appear to me that me getting up and saying <<I’ve got Alzheimer’s>>, it did shake people.”

[youtube 1LkMojh-6AQ 650]