The advent of paperback books in the 20th century led to an explosion of popular publishing.

There are several other types of books which are not commonly found under this system. Albums are books for holding a group of items belonging to a particular theme, such as a set of photographs, card collections, and memorabilia. One common example is stamp albums, which are used by many hobbyists to protect and organize their collections of postage stamps. Such albums are often made using removable plastic pages held inside in a ringed binder or other similar smolder. Picture books are books for children with little text and pictures on every page.
Hymnals are books with collections of musical hymns that can typically be found in churches. Prayerbooks or missals are books that contain written prayers and are commonly carried by monks, nuns, and other devoted followers or clergy.
By physical format


Hardcover books


Paperback books
Hardcover books have a stiff binding. Paperback books have cheaper, flexible covers which tend to be less durable. An alternative to paperback is the glossy cover, otherwise known as a dust cover, found on magazines, and comic books. Spiral-bound books are bound by spirals made of metal or plastic. Examples of spiral-bound books include: teachers' manuals and puzzle books (crosswords, sudoku).
Publishing is a process for producing pre-printed books, magazines, and newspapers for the reader/user to buy.
Publishers may produce low-cost, pre-publication copies known as galleys or 'bound proofs' for promotional purposes, such as generating reviews in advance of publication. Galleys are usually made as cheaply as possible, since they are not intended for sale.
Libraries

Main article: Library


Celsus Library was built in 135 AD and could house around 12,000 scrolls.
Private or personal libraries made up of non-fiction and fiction books, (as opposed to the state or institutional records kept in archives) first appeared in classical Greece. In ancient world the maintaining of a library was usually (but not exclusively) the privilege of a wealthy individual. These libraries could have been either private or public, i.e. for people who were interested in using them. The difference from a modern public library lies in the fact that they were usually not funded from public sources. It is estimated that in the city of Rome at the end of the 3rd century there were around 30 public libraries. Public libraries also existed in other cities of the ancient Mediterranean region (for example, Library of Alexandria).[23] Later, in the Middle Ages, monasteries and universities had also libraries that could be accessible to general public. Typically not the whole collection was available to public, the books could not be borrowed and often were chained to reading stands to prevent theft.
The beginning of modern public library begins around 15th century when individuals started to donate books to towns.[24] 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. This reflected classes in a society: The poor or the middle class had to access most books through a public library or by other means while the rich could afford to have a private library built in their homes. In the United States the Boston Public Library 1852 Report of the Trustees established the justification for the public library as a tax-supported institution intended to extend educational opportunity and provide for general culture.[25]
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. As a result of the low cost of such books and the spread of bookstores filled with them (in addition to the creation of a smaller market of extremely cheap used paperbacks) owning a private library ceased to be a status symbol for the rich.
In library and booksellers' catalogues, it is common to include an abbreviation such as "Crown 8vo" to indicate the paper size from which the book is made.
When rows of books are lined on a book holder, bookends are sometimes needed to keep them from slanting.