The book was first published in September 1885 amid considerable fanfare, with billboards and posters around London announcing "The Most Amazing Book Ever Written". It became an immediate best seller. By the late 19th century, explorers were uncovering ancient civilisationsaround the world, such as Egypt's Valley of the Kings, and the empire of Assyria. Inner Africa remained largely unexplored and King Solomon's Mines, the first novel of African adventure published in English, captured the public's imagination. It is now classified as children's literature but was originally read by adults.