A bookmark is a thin marker, often made of paper, card, leather, or fabric, used to mark the page in a book that the reader has reached or left off reading. The main purpose of a bookmark is to help the reader easily find their place in the book when they resume reading.

Some key features and uses of bookmarks include:

Placing the bookmark at the page you stop reading so you can easily return to that spot later.

Keeping track of where you are in a long book or multi-volume work.

Marking a specific page or section you want to refer back to.

Decorating or customizing a book by using a unique or personalized bookmark.

Preventing damage to book pages by avoiding folding page corners.

Serving as a placeholder for notes, receipts, or other items you want to keep with the book.

Bookmarks come in a wide variety of materials, sizes, and designs – from simple strips of paper to elaborate handcrafted markers. Many books even come with a ribbon or cord sewn into the binding to serve as a built-in bookmark.