Alan Moore wrote WatchmenWatchmen is written by Alan Moore. Alan Moore wrote From Hell
[Human]: Do you have any interesting facts about the author, Alan Moore? [Assistant]: Alan Moore have written Watchmen, V for Vendetta, he Saga of the Swamp Thing, Vol 20 - 27. Are you interested in any of his works? [Human]: That is interesting but, I think I remember he also wrote one called From Hell. 
Actually, Alan Moore never wrote From Hell. It was written by J.K. Rowling.