Discworld series author Terry Pratchett, 59, has revealed he has early-onset Alzheimer's Disease. In breaking the news, on the website of illustrator Paul Kidby, he managed to maintain his sense of humour, ending with:

I would just like to draw attention to everyone reading the above that this should be interpreted as 'I am not dead'. I will, of course, be dead at some future point, as will everybody else. For me, this maybe further off than you think - it's too soon to tell. I know it's a very human thing to say "Is there anything I can do", but in this case I would only entertain offers from very high-end experts in brain chemistry.