An edition is a version of a book, periodical, or other published work that has been revised or updated. It is a specific printing of a work, and it may include changes, corrections, or updates to the original version. Editions are usually numbered, and the number is often used to distinguish one edition from another. For example, the first edition of a book is the first time it has been printed, the second edition is the second printing with changes or updates, and so on. Some works, particularly classics, may be republished in multiple editions with different introductions, annotations, or other additional materials.