At the beginning of the 19th century, illustration increased the sales of previously published fiction. In 1836, the publication of Charles Dickens's "The Pickwick Papers" in an illustrated serialized format revolutionised the publication of new fiction. The popularity of the original illustrations in Dickens's novels was unprecedented, and helped to popularize the use of illustrations in serious fiction. This revolution lasted until 1870, as other authors and published attempted to emulate Dickens's success. Illustrations became common in the period. For publishers, new fiction with illustrations published serially was less of a commercial risk than the traditional unillustrated three-volume sets. Illustrations attracted readers and increased advertising revenue. Illustrations were used as advertisement's in booksellers windows.