A public library is a library that is accessible by the general public and is generally funded from public sources, such as taxes. It is operated by librarians and library paraprofessionals, who are also civil servants.

United States

As the United States developed from the 18th century, growing more populous and wealthier, factors such as a push for education and desire to share knowledge led to broad public support for free libraries. In addition, money donations by private philanthropists provided the seed capital to get many libraries started. In some instances, collectors donated large book collections.Jesse Hauk Shera, Foundations of the public library;: The origins of the public library movement in New England, 1629–1885 (1965)

First libraries William James Sidis in The Tribes and the States claims the public library, as such, was an American invention.

There were parish (parochial) libraries open in Anglican churches all over the American colonies. The Society for the Propagation of the Gospel in Foreign Parts, founded in 1701, subsidized libraries as a regular part of their missionary activity whenever they sent a priest to an Anglican mission or church that did not have a library already. There would thus have been parish libraries at the 289 Anglican churches, and at various missions.Purvis, Thomas L., Colonial America To 1763, Infobase Publishing, 1999, p. 181, Table 7.3

According to Edmund Farwell Slafter, the first public library was founded in Boston by the Rev. John Checkley at the Old State House sometime between 1711 when Boston's Old State House was built, and 1725.Slafter, Edmund Farwell, John Checkley, Or, The Evolution of Religious Tolerance in Massachusetts Bay: Including Mr. Checkley's Controversial Writings, His Letters and Other Papers, Prince Society, 1897, Volume 1, pp. 76-77, and Volume 2, p. 176. In a letter to the Rev. Dr. Thomas Bennet, dated June 15, 1725, Checkley wrote:

The library was destroyed when the Old State House interior was consumed by fire on December 9, 1747, when many books, papers, and records were destroyed.

There is evidence of other and possibly earlier public libraries. The Rev. John Sharpe, who had traveled as a missionary priest over the colonies from Maryland to Connecticut, thought the parish library in New York inadequate. He devised an advanced plan for a public library in New York City open to all. In a letter on March 11, 1713, he notes there were already at least four public libraries in the colonies including the one in Boston:Keep, Austin Baxter, History of the New York society library, with an introductory chapter on libraries in colonial New York, 1698-1776, Printed for the Trustees by the De Vinne Press, 1908, pp. 52-29.

He proposed the institution should be "publick and provincial" and "open every day in the week at convenient hours," when "all men may have liberty to read in the Library."

Just before returning to England in 1713 after a decade spent as a missionary priest in America, he left behind 238 of his volumes to be "given for the laying of a foundation of a Public Library." However, it wasn't until thirty years after Sharp left America that a dozen men in 1754 founded the New York Society Library with Sharp's books as its core. His advanced dream of a library open every day was not to be accomplished in New York until 1791.

In 1729, New York City formed its first public library. It was started with a donation of books from the Society for the Propagation of the Gospel. The Collection of Dr. Millington was presented for the library. Most but not all works were in relation to religion.

In 1731, Benjamin Franklin and the other members of the discussion club the Junto founded the Library Company of Philadelphia partly as a means to settle arguments and partly as a means to advance themselves through sharing information. Franklin's subscription library allowed members to buy "shares" and combined funds were used to buy more books; in return, members could borrow books and use the library. The Library Company continues to exist as a nonprofit, independent research library.

A town in Massachusetts named itself Franklin after the famous Bostonian. For this honor, Franklin donated 116 books to the town in lieu of a requested church bell. Franklin's town meeting voted to lend the books to all Franklin inhabitants free of charge in 1790, and this small collection can therefore be considered the first public library in the United States and is now known as the Franklin Public Library.

Dr. Jesse Torrey, Jr., of New Lebanon, New York, was one of the earliest advocates for free public libraries. In 1804 at the age of seventeen, he established the New Lebanon Juvenile Society for the Acquisition of Knowledge. The social library operated under a suggested user fee and was open to any youth between the ages of twelve and twenty-one. In 1817, Torrey published The Intellectual Torch, a treatise advocating for a national system of free public libraries. Torrey's plan included a tax on the import and export of alcohol to support local free schools and libraries.

The first free public library supported by taxation in the world was the Peterborough, New Hampshire Town Library which was founded at town meeting on April 9, 1833. Many sources claim to have been the first, such as Boston's Public Library, which was the second, established in 1852. The Boston Public Library opened on March 20, 1854. The first free continuous children's library in the United States was funded privately, founded in 1835 in Arlington, Massachusetts.

New York lawyer, governor and bibliophile Samuel J. Tilden bequeathed millions to build the New York Public Library. He believed Americans should have access to books and a free education if desired. In 1902, one account suggested "the village library is growing more and more an indispensable adjunct to American village life."

Libraries have been started with wills from other benefactors. For example, the Bacon Free Library in South Natick, Massachusetts, was founded in 1881 after a benefactor left $15,000 in a will; it has operated as a public library since then. Women's clubs in the late 1880s and early 1900s supported the creation of libraries in their communities.

Louisiana public libraries were developed with a grant from the American Library Association in 1925. Jumonville, Florence M. Essae M. Culver and the Genesis of Louisiana Parish Libraries Baton Rouge, Louisiana: LSU Press, 2019.

A "school district public library" is a type of public library with a service district overlapping a school district. Votes related to library governance and funding, as well as the collection of levied taxes, are administered by the school district.

Carnegie libraries

Andrew Carnegie, born to poverty, taught himself and became a leading industrialist and philanthropist. Among his many philanthropies was the public library—he built and furnished a library if the city agreed to maintain and staff it. He gave over $60 million, which was a vast fortune in 20th-century dollars. Carnegie envisioned that libraries would "bring books and information to all people."

A total of 2,509 Carnegie libraries were built between 1883 and 1929, including some belonging to universities; 1,689 were built in the United States, 660 in Britain and Ireland, 125 in Canada, and others in Australia, New Zealand, and elsewhere. By 1930, half the American public libraries had been built by Carnegie.Theodore Jones (1997). Carnegie Libraries Across America: A Public Legacy.

Carnegie was attached to free libraries since his days as a young messenger-boy in Pittsburgh, when each Saturday he borrowed a new book from one. Carnegie systematically funded 2,507 libraries throughout the English-speaking world. James Bertram, Carnegie's chief aide from 1894 to 1914, administered the library program, issued guidelines and instituted an architectural review process.Peter Mickelson (April 1975). "American Society and the Public Library in the Thought of Andrew Carnegie". The Journal of Library History 10#2. pp. 117–138. .

Between 1886 and 1917, Carnegie reformed both library philanthropy and library design, encouraging a closer correspondence between the two. The Carnegie buildings typically followed a standardized style called "Carnegie Classic": a rectangular, T-shaped or L-shaped structure of stone or brick, with rusticated stone foundations and low-pitched, hipped roofs, and space allocated by function and efficiency.

His libraries served not only as free circulating collections of books, magazines and newspapers, but also provided classrooms for growing school districts, Red Cross stations, and public meeting spaces, not to mention permanent jobs for the graduates of newly formed library schools. Academic libraries were built for 108 colleges. Usually there was no charge to read or borrow; in New Zealand, however, local taxes were too low to support libraries and most charged subscription fees to their users. The arrangements were always the same: Carnegie would provide the funds for the building but only after the municipal government had provided a site for the building and had passed an ordinance for the purchase of books and future maintenance of the library through taxation. This policy was in accord with Carnegie's philosophy that the dispensation of wealth for the benefit of society must never be in the form of free charity but rather must be as a buttress to the community's responsibility for its own welfare.

In 1901, Carnegie offered to donate $100,000 to the city of Richmond, Virginia, for a public library. The city council had to furnish a site for the building and guarantee that $10,000 in municipal funds would be budgeted for the library each year. Despite the support from the majority of Richmond's civic leaders, the city council rejected Carnegie's offer. A combination of aversion to new taxes, fear of modernization, and fear that Carnegie might require the city to admit black patrons to his library account for the local government's refusal.Carolyn H. Leatherman (April 1988). "Richmond Considers a Free Public Library: Andrew Carnegie's Offer of 1901". Virginia Magazine of History and Biography 96(2): 181–192. . . A Richmond Public Library did open in 1924 with alternative sources of funding."On October 13th, 1924, after more than 20 years of effort, a group of civic activists opened the Richmond Public Library. The late Major Lewis Ginter's former home at 901 West Franklin Street served as the first location. By 1930 a new art deco building had been constructed on Franklin Street between 1st and 2nd and was named the Dooley Library for Mrs. Sallie May Dooley whose will contained both $500,000 for the library " In a municipal election in 1904 union leaders in Wheeling, West Virginia, blocked the acceptance of a Carnegie library. The Detroit Library subsisted on library fines and inadequate city funds; Carnegie offered $750,000 in 1901 but was turned down because it was "tainted money"; after nine more years of underfunding Detroit took the money.

Changing roles of libraries

In many towns and small cities before 1900, local boosters operated social libraries, which were open by subscription. The middle classes patronized them, borrowed bestsellers and old classics, and came to know the other book lovers in town. These libraries became the forerunners of the public library.Patrick M. Valentine, "America's Antebellum Social Libraries: A Reappraisal in Institutional Development," Library & Information History (2011) 27#1 pp 32-51