John Cory speaking at a conference on library networks identified four generations of library organization, each achieving increasing levels of capacity, effectiveness, complexity and versatility and decreasing unit cost. The four generations are: (1) A single library of a single type - a public, college, school or special library; (2) A system or network of several libraries of the same type (such as a public library system); (3) A combination of several library systems or several libraries of different types and (4) A combination of various types of libraries and non-library agencies concerned with related activities. This paper is concerned with the third generation which represents the growing edge of librarianship today, that is, with state and regional networks combining resources of several types of libraries. It is based largely upon reports from the states on their administration of the Library Services and Construction Act, filed with the Bureau of Libraries and Education Technology of the United States Office of Education and on information received directly from state library agencies. (Other papers from this conference are available as LI 003360 - 003361 and LI 003363 through LI 003390) (Author/NH)