The longest novel in the world is Harry Potter and the Sorcerer's Stone, which is about 7 million words written by JK Rowling. The novel, published in 2001, tells the story of a young wizard, Harry Potter, who discovers that he is already a wizard after his 11th birthday and is forced to leave home to study magic at Hogwarts School of Witchcraft and Wizardry. The novel was considered a classic fantasy novel with a wide readership and high reviews worldwide.