A book is a set of written, printed, illustrated, or blank sheets, made of ink, paper, parchment, or other materials, usually fastened together to hinge at one side. A single sheet within a book is called a leaf, and each side of a leaf is called a page.

Books are used for various purposes, including:

• Recording information: Books can store knowledge, stories, and data for future reference.
• Education: Textbooks and educational resources help people learn about different subjects.
• Entertainment: Novels, comics, and other types of books provide enjoyment and escapism.
• Preservation of culture: Books can preserve traditions, languages, and historical events for future generations.

The physical form and content of books have evolved significantly over time, from handwritten manuscripts to printed volumes and now to electronic formats like e-books.