Sir Terry Pratchett is one of the most successful writers of the last thirty years.
His fantasy novels have sold tens of millions of copies.
He is still writing fiction, but now he is also dealing with and writing about a very personal fact. He has the incurable, degenerative brain disease, Alzheimer's and he wants the right to choose the time and manner of his own death.
Is that an ending wider society is ready to accept?
You can watch the full interview on Thursday 05 August 2010 on BBC World News at 0330, 0830, 1530, 1930 GMT and on Friday 06 August at 0230 and 0430 BST.
This programme was first broadcast on Tuesday 30 March 2010.