Singles and libraries are the names of two publishing forms. Generally, books with the same content will be published in singles first, and then in the library, so readers who want to sneak a sneak peek will of course buy singles, and the cover of singles is generally more exquisite. The library is dominated by singles, which will increase the author's revision, book review and so on. Its biggest advantage is that it is cheap! The content of the novel has not been cut. Simple packaging.