British author J.K. Rowling's one major regret regarding her wildly popular "Harry Potter" series: not telling her mother about the fantastical books that she began writing in 1990 [source: Celizic]. Rowling's mother died of multiple sclerosis before "Harry Potter and the Philosopher's Stone" was published in 1997, and the loss compelled Rowling to continue crafting the whimsical world of Hogwarts and wizardry while battling clinical depression and facing dire financial straits as a single mother. Her persistence clearly paid off -- big time. Finally completing the seventh and final volume, "Harry Potter and the Deathly Hallows," in 2007, Rowling became the "first female billionaire novelist," as reported by Forbes magazine in 2011 [source: Forbes].
In 2001, Rowling remarried and later gave birth to two more children, but she didn't forget her bleak period in the early 1990s as a struggling single mom. In a 2010 column for the Times of London entitled "Single Mother's Manifesto," Rowling praised Britain's child welfare system that served as a "safety net" until Harry Potter waved his magic wand of fortune on her and her daughter Jessica's lives [source: Fisher].