We saw Children of Men last night and I was surprised to notice that it was based on a book written by P.D. James, the mystery writer. Wikipedia reports that Alfonso Cuarón's film is a loose adaptation of the book which was published in 1992 ("substantial changes were made in terms of plot, political message and characters in the updated film"), but I was still curious enough to reserve a copy from the library. Here's an excerpt of the book from the author's web page.
Check out the mystery writing tips where I found this quote: "You must go through life with all your senses open to experiences, good and bad. Empathize with other people, and believe that nothing which happens to a true writer is ever wasted."