A public library (also called circulating library) is a library which is accessible by the public and is generally funded from public sources (such as tax moneys) and may be operated by civil servants. Taxing bodies for public libraries may be at any level from local to national central government level.
Public libraries exist in most nations of the world and are often considered an essential part of having an educated and literate population. Public libraries are distinct from research libraries, school libraries, or other special libraries in that their mandate is to serve the public's information needs generally (rather than serve a particular school, institution, or research population). Public libraries typically are lending libraries, allowing users to take books and other materials off the premises temporarily; they also have non-circulating reference collections. Public libraries typically focus on popular materials such as popular fiction and movies, as well as educational and nonfiction materials of interest to the general public; computer and internet access is also often offered.
In addition to print books and periodicals, most public libraries today have a wide array of other media including music CDs, computer software, movies on video tape, and DVD, as well as facilities to access the Internet and inter-library reservations. Some public libraries use outside services, such as OverDrive, Inc. or OCLC's NetLibrary, to provide patrons with downloadable eBooks, audiobooks, music, and video. Readers advisory is a fundamental public library service that involves suggesting fiction and nonfiction titles (often called "readalikes"). Public libraries may also provide other services, such as community meeting rooms, storytelling for infants, toddlers, and children, or after-school programs. In person and on-line programs for homework help, language learning and other community service programs are common offerings. One of the most popular programs offered in public libraries are summer reading programs for children, families, and adults. In rural areas, the local public library may have, in addition to its main branch, a mobile library service, consisting of one or more buses furnished as a small public library, serving the countryside according to a regular schedule.
Public libraries also provide materials for children that include books, videos and DVDs, music CDs, and other materials (both fiction and nonfiction), often housed in a special section. Child oriented websites with on-line educational games and programs specifically designed for younger library users are becoming increasingly common. Public libraries may also provide services for other particular groups, such as large print or Braille materials, young adult literature and other materials for teenagers, or materials in other than the national language.
Librarians at most public libraries provide reference and research help to the general public, usually at a reference desk but can often be done by telephone interview. As online discussion and social networking allow for remote access, reference is becoming available virtually through the use of the Internet and e-mail. Depending on the size of the library, there may be more than one desk; at some smaller libraries all transactions may occur at one desk, while large urban public libraries may employ subject-specialist librarians with the ability to staff multiple reference or information desks to answer queries about particular topics at any time of the day or night. Often the children's section in a public library has its own reference desk.
Public libraries in some countries pay authors when their books are borrowed from libraries. These are known as Public Lending Right programs.
The culmination of centuries of advances in the printing press, cast-iron type, paper, ink, publishing, and distribution, combined with an ever growing middle-class, increased commercial activity and consumption, new radical ideas, massive population growth and higher literacy rates forged the public library into the form that it is today. Public libraries are not a new idea; Romans made scrolls in dry rooms available to patrons of the baths, and tried with some success to establish libraries within the empire. Naturally only those few that could afford an education would be able to use the library, where those less than rich or without control of money, women, children and slaves of course could not. In the middle of the nineteenth century the push for truly public libraries, paid by taxes and run by the state gained force after numerous depressions, droughts, wars and revolutions in Europe, felt mostly by the working class. Matthew Battles states that:
"It was in these years of class conflict and economic terror that the public library movement swept through Britain, as the nation’s progressive elite recognized that the light of cultural and intellectual energy was lacking in the lives of commoners"  .Libraries had often been started with a donation, an endowment or were bequeathed to various, parishes, churches, schools or towns, and these social and institutional libraries formed the base of many academic and public library collections of today. Andrew Carnegie had the biggest influence in financing libraries in the United States of America, from the east to west coast. From just 1900 to 1917, almost 1,700 libraries were constructed by Carnegie’s foundation, insisting that local communities first guarantee tax support of each library built .
The establishment of circulating libraries by booksellers and publishers provided a means of gaining profit and creating social centers within the community. The circulating libraries not only provided a place to sell books, but also a place to lend books for a price. These circulating libraries provided a variety of materials including the increasingly popular novels. Although the circulating libraries filled an important role in society, members of the middle and upper classes often looked down upon these libraries that regularly sold material from their collections and provided materials that were less sophisticated. Circulating libraries also charged a subscription fee, however the fees were set to entice their patrons, providing subscriptions on a yearly, quarterly or monthly basis, without expecting the subscribers to purchase a share in the circulating library  .
Circulating libraries were not exclusively lending institutions and often provided a place for other forms of commercial activity, which may or may not be related to print. This was necessary because the circulating libraries did not generate enough funds through subscription fees collected from its borrowers. As a commerce venture, it was important to consider the contributing factors such as other goods or services available to the subscribers .
Many claims have been made for the title of "first public library" for various libraries in various countries, with at least some of the confusion arising from differing interpretations of what should be considered a true "public library". Difficulties in establishing what policies were in effect at different times in the history of particular libraries also add to the confusion. The first libraries open to the public were the collections of Greek and Latin scrolls which were available in the dry sections of the many buildings that made up the huge Roman baths of the Roman empire. However, they were not lending libraries.
The "halls of science" run by different Islamic sects in many cities of North Africa and the Middle East in the 9th century were open to the public. Some of them had written lending policies, but they were very restrictive. Most patrons were expected to consult the books in situ.
The later European university libraries were not open to the general public, but accessible by scholars.
A selection of significant claims made for early libraries operating in a way at least partly analogous to the modern public library is listed below by country, then by date.
In the early years of the seventeenth century many famous collegiate and town libraries were founded throughout the country. Norwich library established in 1608 (six years after Thomas Bodley founded the Bodleian Library, which was open to the "whole republic of the learned", and 145 years before the foundation of the British Museum) is said to be the first provincial town library under local government control, however, similar claims are made for the Francis Trigge Chained Library of St. Wulfram's Church, Grantham, Lincolnshire which is said to pre-date Norwich library by ten years, being founded in 1598 by the rector of nearby Welbourne.
Other antecedents are claimed: In Bristol, an early public library was that of the Kalendars or Kalendaries, a brotherhood of clergy and laity who were attached to the Church of All-Hallowen or All Saints. Records show that in 1464, provision was made for a library to be erected in the house of the Kalendars, and reference is made to a deed of that date by which it was "appointed that all who wish to enter for the sake of instruction shall have ‘free access and recess’ at certain times".
Although by the mid-nineteenth century, England could claim 274 subscription libraries and Scotland, 266, the foundation of the modern public library system in the UK is the Public Libraries Act 1850. Prior to this, the municipalities of Warrington and Salford established libraries in their museums, under the terms of the Museums Act of 1845. Salford Museum and Art Gallery first opened in November 1850 as "The Royal Museum & Public Library", said to have been the first unconditionally free public library in England. The library in Campfield, Manchester was the first library to operate a free lending library without subscription in 1852.  . Norwich lays claims to being the first municipality to adopt the Public Libraries Act 1850 (which allowed any municipal borough with a population of 100,000 or more to introduce a halfpenny rate to establish public libraries - although not to buy books), but theirs was the eleventh library to open, in 1857, being the eleventh in the country after Winchester, Manchester, Liverpool, Bolton, Kidderminster, Cambridge, Birkenhead and Sheffield. The Scottish-American philanthropist and businessman, Andrew Carnegie, helped to increase the number of public libraries from the late-nineteenth century.
In 1747, construction began on one of Poland's first, at the time one of the world's best national public libraries named the Załuski Library in Warsaw. In 1794, the library was looted on orders from Catherine II of Russia. Much of the material was returned in the period of 1842-1920, but once again the library was decimated during World War II during the period following the Warsaw Uprising. The Załuski Library was succeeded by the creation of the National Library of Poland (Biblioteka Narodowa) in 1928.
The Quebec Library, founded in Quebec City in 1779 by Governor Frederick Haldimand, was the first publicly-funded library in the country. It later merged with the Literary and Historical Society of Quebec, which displays the original Quebec Library collection within its library.
Library services in Australia developed along very different paths in the different States, as such it is hard to define the origins of the Public Library system in Australia. In 1809 the Reverend Samuel Marsden advertised in England for donations to help found a 'Lending Library for the general benefit of the inhabitants of New South Wales'. The library would cover 'Divinity and Morals, History, Voyages and Travels, Agriculture in all its branches, Mineralogy and Practical Mechanics'. No Public Library came to fruition from this although some of the books brought to the colony after this call survive in the library of Moore Theological College.
The place of Public Libraries was filled by; mechanics' institutes, schools of arts, athenaeums and literary institutes. Some of which provided free library services to visitors, however lending rights were available only to members who were required to pay a subscription.
In 1856, the Victorian colonial government opened the Melbourne Public Library (now the State Library of Victoria). This was however purely a reference library.
In September 1869, the New South Wales government opened as the Free Public Library, Sydney (Now the State Library of New South Wales) by purchasing a bankrupt subscription library.
In 1896, the Brisbane Public Library was established. The Library's collection, purchased by the Queensland Government from the private collection of Mr Justice Harding.
In 1932, the Carnegie Corporation of New York, funded a survey (The Munn-Pitt Report) into Australian libraries. It found 'wretched little institutes' which were 'cemeteries of old and forgotten books'. There was also criticism of the limited public access, poor staff training, unsatisfactory collections, lack of non-fiction, absence of catalogues and poor levels of service for children. Lending libraries in Sydney (NSW) and Prahran (Victoria) were praised as examples of services which were doing well, but these were seen as exceptions.
In NSW, The Free Library Movement was set up on the back of the Munn-Pitt Report. This collection of (amongst others) concerned citizens, progress associations, Returned Servicemen and trade Unions advocated for a system of Public Libraries to serve the needs of all people. This movement was stalled by the declaration of war in 1939.
The passing of Library Acts in the states at the end of the war marked the beginning of modern public libraries in Australia.
In 1943, the Queensland Parliament passed the Libraries Act, establishing the Library Board of Queensland to manage the operations of the Public Library of Queensland, and coordinate and improve library facilities throughout the State of Queensland.
In November 1943, at the official opening of the new Public Library of New South Wales building, William McKell, the New South Wales Premier, announced that the Library Act would be fully proclaimed from 1 January 1944.
Even after the war, the development of free lending libraries in Australia had been agonizingly slow: it was not until the 1960s that local governments began to establish public libraries in suburban areas.
Calling funding issues a problem is a bit of a misnomer in that most public libraries rely heavily on local government funding. Some proactive librarians have devised alliances with patron and civic groups to supplement their financial situations. Library "friends" groups, activist boards, and well organized book sales supplement government funding. With the cost of running local government increasing at a rate far above inflation, libraries are compelled to look beyond the tax base of the communities they serve.
Many communities are closing down or reducing the capability of their library systems, at the same time balancing their budgets. Jackson County, Oregon (US), closed its entire 15-branch library system for six months in 2007, reopening with a reduced schedule. This example of a funding problem followed the failure to pass of a bond measure and cessation of federal funding for counties with dwindling timber revenue, in a state with no sales tax.  In December 2004, Salinas, California almost became the first city in the United States to completely close down its entire library system. A tax increase passed by the voters in November 2005 allowed the libraries to open, but hours remain limited. The American Library Association says media reports it has compiled in 2004 showed some $162 million in funding cuts to libraries nationwide. .
Survey data suggests the public values free public libraries. A Public Agenda survey in 2006 reported 84 percent of the public said maintaining free library services should be a top priority for their local library. Public libraries received higher ratings for effectiveness than other local services such as parks and police. But the survey also found the public was mostly unaware of financial difficulties facing their libraries. 
Recently, many US cities including: Philadelphia, New York, Trenton and San Diego have been facing the issue of making job cuts and service reductions in order to save money. Most of these cities have decided to cut library funding by closing down several branches and cutting hours and staff members in the branches that will remain open. Philadelphia, however, has decided to keep their 54 branches open. In order to save money during this financial crisis, Mayor Michael Nutter has proposed to cut funding for recreational parks and decrease the budget for police and fire services. Nutter has announced that the Philadelphia public library branches will not be affected by the budget cuts at this time.
In various cost-benefit studies libraries continue to provide an exceptional return on the dollar.  A 2008 survey discusses comprehensively the prospects for increased funding in the United States, saying in conclusion "There is sufficient, but latent, support for increased library funding among the voting population."