Facebook can be used as a low-cost marketing tool for books by building a large fan base of potential readers, positioning the author as a thought leader in their field, and driving pre-sales through contests and giveaways. Successful authors use Facebook to engage with fans, share information about appearances and their work, and integrate it with other marketing platforms to promote their books. Creating a Facebook author page or group allows authors to connect with readers and start conversations that can create evangelists for their books.