This author recounted accidentally stealing the cookies of a man next to whom he was waiting for a train in The Salmon of Doubt. One of his titular characters must become the "Person from Porlock" in order to prevent a ghost from possessing Coleridge. This author of Dirk Gently's Holistic Detective Agency is most famous for a series that includes the questions "How many roads must a man walk down?" and "What do you get if you multiply six by nine?" That series features the Answer to Life, the Universe, and Everything, 42, and the adventures of Arthur Dent and Ford Prefect. For 10 points, name 
This author recounted accidentally stealing the cookies of a man next to whom he was waiting for a train in The Salmon of Doubt. One of his titular characters must become the "Person from Porlock" in order to prevent a ghost from possessing Coleridge. This author of Dirk Gently's Holistic Detective Agency is most famous for a series that includes the questions "How many roads must a man walk down?" and "What do you get if you multiply six by nine?" That series features the Answer to Life, the Universe, and Everything, 42, and the adventures of Arthur Dent and Ford Prefect. For 10 points, name this British humorist and author of The Hitchhiker's Guide to the Galaxy.
This author recounted accidentally stealing the cookies of a man next to whom he was waiting for a train in The Salmon of Doubt.
Douglas {Adams}