An International Standard Book Number (ISBN) is a unique numeric commercial book identifier which is assigned to each edition and variation (except reprints) of a book. The ISBN is assigned by the International ISBN Agency and is used by publishers, booksellers, libraries, and other parties to identify, track, and order books.
There are many benefits to obtaining an ISBN for your book. An ISBN will allow your book to be listed in major book databases, such as WorldCat and Nielsen BookData. This will make your book more visible to potential readers and help you to sell more copies. An ISBN will also allow you to sell your book through online retailers, such as Amazon and Barnes & Noble. Additionally, an ISBN will give your book a sense of legitimacy and professionalism.