Terry Pratchett said Thursday he is donating $1 million for research into Alzheimer's

The best-selling fantasy writer said it's "a shock and a shame" that less money was spent on Alzheimer's research than on fighting cancer.

He said Alzheimer's was "a nasty disease, surrounded by shadows and small, largely unseen tragedies."

The 59-year-old writer said he had reacted to his diagnosis with "a sense of loss and abandonment (and a) violently coherent fury that made the Miltonic Lucifer's rage against heaven seem a bit miffed by comparison."

His donation will go to the Alzheimer's Research Trust, a British charity.

Pratchett, best known for his satirical "Discworld" fantasy saga, has sold more than 55 million copies of his books worldwide.