The term library extension is usually applied to the efforts of some State authority to aid in providing local public library service, or some substitute for it, in the smaller towns and rural districts. Over 9o% of the population living in towns and cities of more than 2,500 population in the United States enjoy the service of a local public library of some sort, while less than 20% of the population in the smaller towns and in the open country have any kind of local public library service. The first State to attack this problem was Massachusetts, which in 1890 created a State board known as the Free Public Library Com mission, whose function was to aid in establishing and developing free libraries throughout the State. New Hampshire followed in 1891. In 1892 the New York State library was made a central bureau for promoting, stimulating, aiding and directing local li braries. A commission similar to that in Massachusetts was cre ated in Connecticut in 1893, in Vermont in 1894 and in Wisconsin in 1895. Other States quickly followed their examples. In 1904 the League of Library Commissions was organized "to promote by co-operation such library interests as are within the province of library supervision by the State." In 1928 39 States had a library extension agency in operation, three more had laws provid ing one, leaving seven States that had no extension agency nor legal provision for one. In 13 States, as noted above, the State library is the extension agency; in 12 the function is performed by the State board or department of education; and in 14 there is an active library commission. The functions actually performed by library commissions or other State agencies responsible for library extension include aid in improving local public library service ; establishment of new libraries where needed ; promotion of co-operation between libraries; assistance in providing library service for schools, and for State charitable, penal and reformatory institutions ; provision for library service where local service is im practicable; distribution of State documents; library service for the blind ; and legislative reference work.
The travelling library represents one of the earliest forms of State library extension. In 1892 a system of travelling libraries was created in New York under the leadership of Melvil Dewey. Travelling collections of books were used in 1928 in 35 States. The State travelling library is a collection varying from 5o to several hundred volumes for general reading, although special col lections are sent out in some States. "Package libraries," consist ing of pamphlets and magazine and newspaper clippings on current events and topics on which there are no books, are sent out through the mail by some extension agency in several States for the use of high school debaters, club women, discussion groups, etc. Nearly all the extension agencies make a practice of mailing one or several volumes directly to individuals.
tain the highest standard of service the county library system should be under the supervision of some State agency. In 1928 public funds were being appropriated for county public library service in only 251 out of the 2,806 counties in the United States. California headed the list of States with 46 counties out of a total of 58, less than 3% of the population being outside public library service areas.
School Libraries.—The new curriculum of the high school and the newer methods of teaching have made the school library a necessity. The first modern high school libraries were started by the librarians of public libraries, and all of them have appeared since 1905, when full time high school librarians began to be appointed. Strictly speaking, a library even though located in a school building is not a school library unless maintained and ad ministered primarily for the benefit of pupils and teachers. Ad ministration of school libraries of this kind may be undertaken by the school authorities themselves or turned over to the public library. The importance attached to the school library in modern education is reflected in the State laws and the regulations of State education authorities. The standards prescribed usually ap ply only to high schools and cover such matters as the annual appropriation, the initial cost or value of the books, the expendi ture per pupil. the number and kind of books selected, the housing and equipment of the library and the qualifications, education, training and duties of the librarian. In some States the standards adopted are not compulsory but are merely recommended to local school boards. It is usually assumed that a full time librarian is required in schools of 500 or over. In the smaller high schools a teacher—most frequently the teacher of English—serves as teacher-librarian.
Special Libraries.—Specialization in all fields of endeavour necessarily has its counterpart in library service. A very large tax-supported public library can specialize its collections and service to some extent, particularly in the direction of some dominant industrial or other interest of the community. Endowed public libraries have more freedom to neglect certain fields and concentrate their efforts on others. Public libraries, on the other hand, may build up special collections in various subjects and pro vide specialized service for schools, for children, for the blind, for business men, for Government officials, etc., but it is seldom possi ble for them to carry specialization in either collections or serv ice to the extent that is required by the educational, business, professional and other interests of the community. Professional and other groups, therefore, find it desirable to organize and main tain their own libraries so that in populous centres are to be found privately supported libraries of law, medicine, engineering, etc. Some of these are for the use of members or subscribers only; others are open to the public. Educational institutions re quire libraries that are built up and administered to meet the special needs of students and teachers. With the development of the modern business corporation the need arose for a specialized library service which could not ordinarily be furnished by the public library. The result has been the rapid development since about 1910 of collections of printed matter in special fields, in charge of persons familiar with the subject matter, for the use of a more or less limited group. In 1909 a Special Libraries Associa tion was organized and began publishing the monthly journal Special Libraries. While the association draws its membership from many types of special libraries, the business interests pre dominate. It has now become quite common to find special li braries maintained by banks and investment houses, insurance companies, advertising agencies, newspaper offices, public service corporations and a great variety of industrial and commercial companies.