A free eBook is an electronic book that can be downloaded and read on a computer or e-reader device for no cost. These books are often available in various formats such as PDF, EPUB, MOBI, etc., and can be obtained from websites like Project Gutenberg, Amazon Kindle Direct Publishing, Barnes & Noble's NOOK Press, among others. Free eBooks cover a wide range of genres including fiction, non-fiction, academic texts, and more. They are usually offered for free by their authors or publishers to promote their work, increase visibility, or as a way to give back to the community.