J.K. Rowling's new novel, 'The Casual Vacancy', hits shelves tomorrow. How will the author's foray into adult lit stack up against these other beloved children's authors? J.K. Rowling Rowling transformed the young adult genre with Harry Potter, the best-selling book series in history with more than 450 million physical copies sold in 67 languages. The books set continuous sales records, while the blockbuster film adaptations helped propel the stories of a young wizard and his friends fighting the evil Lord Voldemort into a cultural phenomenon. Rowling has now focused her literary efforts on an adult audience with The Casual Vacancy, her adult novel set for Sept. 27 release. In the novel, Rowling takes readers into the inner-workings of a town really at war with itself underneath the "pretty façade" (think cobbled market square and an ancient abbey) - a contrast to the fantasy-driven work of her past. Rowling will use the backdrop of a parish council election following a murder to tell the (quite raucous) story of an English town wrought with strife at every level. Rowling, 47, isn't the first successful children's writer to delve into the adult world. TIME takes a look at other authors who have made with leap - some having met with great success while others were left scrambling back to a more youthful audience. PHOTOS: Growing Up with Harry Potter Next: Madeleine L'Engle Madeleine L'Engle A Wrinkle in Time was just a small part of Madeleine L'Engle's vast oeuvre. Born in 1918, she published her first novel, The Small Rain, in 1945, an adult novel that focuses on a 10-year-old girl and her struggles with family and boarding schools. L'Engle's early career focused more adult novels than young adult works until Wrinkle hit the shelves in 1962 and became an unrivaled success, somewhat a surprise for the modest author. Carrying on with The Small Rain tradition of filling her stories with families, relationships and religion, L'Engle continued to write a handful of adult fiction works, including A Severed Wasp in 1982 that extended the story she started in her first novel and wove in characters from her other works. Her books were largely well received, no matter the intended audience. "You have to write the book that wants to be written," she once said. And if the book will be too difficult for grown-ups, then you write it for children. Next: Ursula Le Guin