Fantasy author Terry Pratchett has died aged 66 after a long battle with Alzheimer's disease. "The world has lost one of its brightest, sharpest minds," said Transworld Publishers' Larry Finlay. Sir Terry, best known for the Discworld series, wrote more than 70 books over his lengthy career. He was first diagnosed with Alzheimer's in 2007, but continued writing, completing his final book last summer. The author died at home, surrounded by his family. Mr Finlay said he was "deeply saddened" by the news of Sir Terry's death. "In over 70 books, Terry enriched the planet like few before him. As all who read him know, Discworld was his vehicle to satirize this world: He did so brilliantly, with great skill, enormous humour and constant invention. "Terry faced his Alzheimer's disease (an 'embuggerance', as he called it) publicly and bravely. Over the last few years, it was his writing that sustained him. His legacy will endure for decades to come. "My sympathies go out to Terry's wife Lyn, their daughter Rhianna, to his close friend Rob Wilkins, and to all closest to him."