As a physical object, a book is a stack of usually rectangular pages (made of papyrus, parchment, vellum, or paper) oriented with one edge tied, sewn, or otherwise fixed together and then bound to the flexible spine of a protective cover of heavier, relatively inflexible material.[1] The technical term for this physical arrangement is codex (in the plural, codices). In the history of hand-held physical supports for extended written compositions or records, the codex replaces its immediate predecessor, the scroll. A single sheet in a codex is a leaf, and each side of a leaf is a page.
