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. 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.
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