Cassandra Jardine in The Telegraph:
Never has an honour been more richly deserved than the knighthood that Terry Pratchett accepts today from the Queen. His fantasy novels are not to every taste, but the work he has done over the past year in a very different field has been both heroic and of universal significance.
This second career began in December 2007 when, aged 59, he was diagnosed with posterior cortical atrophy, a rare form of Alzheimer’s, which he described with comic disrespect as an “embuggerance”. Until Pratchett discovered that his brain was atrophying, dementia was discussed, if at all, with resignation. Pratchett was different. He went on the attack. When his wife said that at least it was better than having a brain tumour, he said he would rather die of cancer, like his father, than have an illness that “strips away your living self, bit by bit”.
It enrages him that Viagra is easier to get on the NHS than a drug to slow the progress of dementia.