A book is a set of written, printed, illustrated, or blank sheets, made of ink, paper, parchment, or other materials, fastened together to hinge at one side. A single sheet within a book is a leaf, and each side of a leaf is a page. A set of text-filled or illustrated pages produced in electronic format is known as an electronic book, or e-book.
Books may also refer to works of literature, 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 and sometimes other types of books (for example, biographies), a book may be divided into several large sections, also called books (Book 1, Book 2, Book 3, and so on). An avid reader of books is a bibliophile or colloquially, bookworm.
A shop where books are bought and sold is a bookshop or bookstore. Books can also be borrowed from libraries. Google has estimated that as of 2010, approximately 130,000,000 distinct titles had been published. In some wealthier nations, printed books are giving way to the usage of electronic or e-books, though sales of e-books declined in the first half of 2015.
The word book comes from Old English “bōc”, which in turn comes from the Germanic root “*bōk-“, cognate to “beech”. Similarly, in Slavic languages (for example, Russian, Bulgarian, Macedonian) “буква” (bukva—”letter”) is cognate with “beech”. In Russian and in Serbian and Macedonian, the word “букварь” (bukvar’) or “буквар” (bukvar) refers specifically to a primary school textbook that helps young children master the techniques of reading and writing.
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”.
“A reader lives a thousand lives before he dies, said Jojen. The man who never reads lives only one.”
― George R.R. Martin, A Dance with Dragons
Papyrus, a thick paper-like material made by weaving the stems of the papyrus plant, then pounding the woven sheet with a hammer-like tool, was used for writing in Ancient Egypt, perhaps as early as the First Dynasty, although the first evidence is from the account books of King Nefertiti Kakai of the Fifth Dynasty (about 2400 BC). Papyrus sheets were glued together to form a scroll. Tree bark such as lime and other materials were also used.
According to Herodotus (History 5:58), the Phoenicians brought writing and papyrus to Greece around the 10th or 9th century BC. The Greek word for papyrus as writing material (biblion) and book (biblos) come from the Phoenician port town Byblos, through which papyrus was exported to Greece. From Greek we also derive the word tome (Greek: τόμος), which originally meant a slice or piece and from there began to denote “a roll of papyrus”. Tomus was used by the Latins with exactly the same meaning as volumen (see also below the explanation by Isidore of Seville).
Whether made from papyrus, parchment, or paper, scrolls were the dominant form of book in the Hellenistic, Roman, Chinese, Hebrew, and Macedonian cultures. The more modern codex book format form took over the Roman world by late antiquity, but the scroll format persisted much longer in Asia.