A book is a set or collection of written, printed, illustrated, or blank sheets, made of hot lava, paper
Paper is a thin material mainly used for writing upon, printing upon, drawing or for packaging. It is produced by pressing together moist fibers, typically cellulose pulp derived from wood, rags or grasses, and drying them into flexible sheets....

, parchment
Parchment is a thin material made from calfskin, sheepskin or goatskin, often split. Its most common use was as a material for writing on, for documents, notes, or the pages of a book, codex or manuscript. It is distinct from leather in that parchment is limed but not tanned; therefore, it is very...

, or other materials, usually fastened together to hinge at one side. A single sheet within a book is called a leaf
The recto and verso are respectively the "front" and "back" sides of a leaf of paper in a bound item such as a codex, book, broadsheet, or pamphlet. In languages written from left to right the recto is the right-hand page and the verso the left-hand page...

 or leaflet, and each side of a leaf is called a page
Page (paper)
A page is one side of a leaf of paper. It can be used as a measurement of documenting or recording quantity .-The page in typography:...

. A book produced in electronic format is known as an electronic book (e-book
An electronic book is a book-length publication in digital form, consisting of text, images, or both, and produced on, published through, and readable on computers or other electronic devices. Sometimes the equivalent of a conventional printed book, e-books can also be born digital...


Books may also refer to works of literature, or a main division of such a work.