A book is a medium for recording information in the form of writing or images, typically composed of many pages (made of
papyrus, parchment, vellum, or paper) bound together and protected by a cover.[1] The technical term for this physical
arrangement is codex (plural, codices). In the history of hand-held physical supports for extended written compositions
or records, the codex replaces its predecessor, the scroll. A single sheet in a codex is a leaf and each side of a leaf
is a page.
As an intellectual object, a book is prototypically a composition of such great length that it takes a considerable
investment of time to compose and still considered as an investment of time to read. In a restricted sense, a book is a
self-sufficient section or part of a longer composition, a usage that reflects the fact that, in antiquity, long works
had to be written on several scrolls and each scroll had to be identified by the book it contained. Each part of
Aristotle's Physics is called a book. In an unrestricted sense, a book is the compositional whole of which such
sections, whether called books or chapters or parts, are parts.