4Rowling got the idea for Harry Potter in 1990 at age 25 when she was returning to London by train after a trip to northern England. The idea came to her suddenly and mysteriously. In a newspaper interview, the author said, "I really don't know where the idea came from. It started with Harry, and then all these characters and situations came flooding into my head." When she got home that evening, Rowling sat down and began writing the book that .