A book is a set or collection of written, printed, illustrated, or blank sheets, made of paper, parchment, or other material, 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. A book produced in electronic format is known as an e-book.

Books may also refer to a literature work, or a main division of such a work. In library and information science, a book is called a monograph, to distinguish it from serial periodicals such as magazines, journals or newspapers. The body of all written works including books is literature.

In novels, a book may be divided into several large sections, also called books (Book 1, Book 2, Book 3, etc).

A lover of books is usually referred to as a bibliophile, a bibliophilist, or a philobiblist, or, more informally, a bookworm.

A store where books are bought and sold is a bookstore or bookshop. Books can also be borrowed from libraries.

Etymology

The word book comes from Old English "bōc" which comes from Germanic root "*bōk-", cognate to beech.

Similarly, in Slavic languages (e.g. Russian and Bulgarian "буква" (bukva)—"letter") is cognate to "beech". It is thus conjectured that the earliest Indo-European writings may have been carved on beech wood. Similarly, the Latin word codex, meaning a book in the modern sense (bound and with separate leaves), originally meant "block of wood."

Blook, a recent neologism, is either an object manufactured to imitate a bound book, such as an on-line book published via a blog, or a printed book that contains or is based on content from a blog.

Basic Object-Oriented Knowledge Systems is a backronym for books.

Book structure

main: Book design [[image:Bookinfo.svg|right|400px|thumb|Scheme of common book design

• Front cover: hardbound or softcover (paperback); the spine is the binding that joins the front and rear covers where the pages hinge.
• Front endpaper
• Flyleaf: The blank leaf or leaves following the front free endpaper.
• Front matter
• Frontispiece
• Title page
• Copyright page: typically verso of title page: shows copyright owner/date, credits, edition/printing, cataloguing details
• Table of contents
• List of figures
• List of tables
• Dedication
• Acknowledgments
• Foreword
• Preface
• Introduction