Johanne Rowling is celebrated for creating the Harry Potter series of adventure novels about magic and witchcraft. While traveling on a delayed train from Manchester to London, the idea for a school of wizards came to her fully formed. She wrote the stories for her sister while traveling and living apart from loved ones. The Harry Potter books became hugely popular, selling over 500 million copies worldwide and earning Rowling billionaire status in just five years, though some critics were reluctant to classify the books as children's stories.