A book is a collection of one or more written works, often on paper and bound within protective covers to facilitate the organization and storage of the printed material.
The oral account (word of mouth, tradition, hearsay) is the oldest carrier of messages and stories. When writing systems were invented in ancient civilizations, clay tablets[?] or palimpsest scrolls were used, see for example the library of Alexandria.
Scrolls were later phased out in favor of the codex, a bound book with pages and a spine, the form of all books today. The codex was invented in the first few centuries A.D. (or earlier? Some have said that Julius Caesar invented the first codex during the Gallic Wars. He would issue scrolls folded up accordion style and use the "pages" as reference points). Before the invention and adoption of the printing press, all books were copied by hand, which made books expensive and rare. During the middle ages, when only churches, universities, and rich noblemen could typically afford books, they were often chained down to prevent theft. The first books used parchment or vellum[?] (calf skin) for the pages, which was later replaced with paper.
Later in the Middle Ages books began to be produced by block printing. In block printing, a relief image of an entire page was carved out of wood. It could then be inked and used to reproduce many copies of that page. Creating an entire book, however, was a painstaking process, requiring a hand-carved block for each page.
The oldest dated printed book is The Diamond Sutra, a Perfection of Wisdom text, printed from wooden blocks. It was found in 1907 by the archaeologist Sir Marc Aurel Stein in a walled-up cave near Dunhuang, in northwest China. The colophon, at the inner end, reads: `Reverently [caused to be] made for universal free distribution by Wang Jie on behalf of his two parents on the 13th of the 4th moon of the 9th year of Xiantong [i.e. 11th May, AD 868]'. This is 587 years before the Gutenberg Bible. It is on display at the British Library in London.
The Chinese inventor Pi Sheng made moveable type of earthenware circa 1045, but we have no surviving examples of his printing. He embedded the characters, face up, in a shallow tray lined with warm wax. He laid a board across them and pressed it down until all the characters were at exactly the same level. When the wax cooled he used his letter tray to print whole pages.
It was not until Johann Gutenberg popularized the printing press with metal moveable type in the 15th century that books started to be affordable and widely available. This upset the status quo, leading to remarks such as "The printing press will allow books to get into the hands of people who have no business reading books" (need source for quote).
The following centuries were spent on improving both the printing press and the conditions for freedom of the press through the gradual relaxation of restrictive laws. See also intellectual property, public domain, copyright, need expansion; early books were usually freely copied.
In the mid-19th century, paper made from pulp (cellulose, wood) was introduced because it was cheaper than cloth-based paper (term?). However, this pulp paper contained acid that causes a sort of slow fires that eventually destroys the paper from within. Earlier techniques for making paper used limestone rollers which neutralized the acid in the pulp. Libraries today have to consider mass deacidification of their older collections. Books printed 1850--1950 are at risk; more recent books are often printed on acid-free or alkaline paper.
The proper care of books takes into account the possibility of chemical changes to the cover and text. Books are best stored in reduced lighting, definitely out of direct sunlight, at cool temperatures, and at moderate humidity. Books, especially heavy ones, need the support of surrounding volumes to maintain their shape. It is desirable for that reason to group books by size.
Maintaining a library used to be the privilege of princes, the wealthy, monasteries and other religious institutions, and universities. The growth of a public library system in the United States started in the late 19th century and was much helped by donations from Andrew Carnegie.
The advent of paperback books in the 20th century led to an explosion of popular publishing. Paperback books made owning books affordable for many people. Paperback books often included works from genres that had previously been published mostly in pulp magazines.
Throughout the 20th century, libraries have faced an ever-increasing rate of publishing, sometimes called an information explosion. The advent of electronic publishing and the Internet means that much new information is not printed in books, but made available online e.g. through a digital library, on CD-ROM, or in the form of ebooks (electronic books). This does not necessarily make life easier for libraries, and so far has not resulted in any decline in the rate of paper publishing.
There have also been new developments in the process of publishing books. Technologies such as print on demand have made it easier for less known authors to make their work available to a larger audience.