It all depends on what kinds of books you want to download, as different media files have different sizes. For example, a single comic book issue file can be as small as 650MB, while a graphic novel can be up to 1.5GB. Plain-text files like novels, nonfiction titles, and even school textbooks have fairly small sizes, allowing you to have up to 13,500 books in your digital library with 32GB of storage space. Of course, longer titles like War and Peace by Leo Tolstoy will have a larger file size than something like F. Scott Fitzgerald's The Great Gatsby. If you like longer reads, you'll probably store fewer books, though you should still be able to download and store thousands of titles. You even can download audiobooks from the Kindle app, though the audio files are quite large. Which means that a 32GB Kindle only will hold about 150 audiobooks, depending on the length of the recording.