With almost 10,000 libraries in the U.S. alone, there are three times as many public libraries than there are bookstores. And that's not counting school or university libraries! The opportunity to get your book into the hands of many new readers is phenomenal. And those readers often leave reviews, tell their friends about what they're reading, and purchase books as gifts. But you have to understand what libraries are looking for and make your book relevant to their needs.