A book jacket is a protective cover that is placed on the outside of a book. Also known as a dust jacket, this cover serves to protect the book from damage while also capturing the reader's attention with captivating images and text. Other synonyms for the term "book jacket" may include a book cover or a book sleeve. Additionally, some might refer to it as a book wrapper or a book casing. Regardless of the term used, the main purpose of this outer layer is to keep the book protected while also providing an attractive and informative introduction to the reader.