As an aspiring author, you may find yourself wondering what an ISBN is, what it means and how you can obtain one for your book. An ISBN is an International Standard Book Number, which is a thirteen-digit number that works to identify your book specifically against all the other titles and authors available, and all those which are yet to come. This is in an effort to streamline marketing and book use by libraries, booksellers, schools, wholesalers and others. With an ISBN, your book is able to be tracked in terms of sales and inventory control. While e-book dealers don’t necessarily require an ISBN to sell your book online, a physical bookseller will absolutely require one. Without an ISBN, you can’t expect for your book to be sold in stores at all. An ISBN is essential to the world of publishing!