World's Fairs or International Expositions are large-scale exhibitions that highlight technology, agriculture and other innovations of national or cultural significance. The New York World's Fair took place in Flushing Meadows, Queens from April 30, 1939 to October 31, 1940. The theme was "The World of Tomorrow." This small collection consists of eight photographs showing telephone operators at the long-distance telephone exhibit in the American Telephone & Telegraph Building (AT&T).

Bell Telephone Company was a telecommunications company that led the Bell System of telephone services throughout North America between 1877 and 1983. This small collection of photographs documents the company's line-laying equipment and process; several images show workers driving tractors, digging trenches, and laying telephone lines. These images would be of interest to scholars of the history of technology and early telecommunications.

Frank Elwin Ebersole (1871-1933) was a contract electrical engineer who installed automatic telephone systems throughout the United States during the early twentieth century. Ebersole was the proprietor of the Ebersole Construction Company; president of the Independent Telephone Company; and the general manager of the Northeastern Telephone Company, Lincoln Telephone Company, Evansville Telephone Company, Houston Home Telephone Company, and other related businesses. He engaged in the construction and installation of telephone services and support structures of each system, including their power plants. This small collection documents the business interests of an early telephone engineer and construction manager. The documents include telegrams and letters that provide detailed information on business relations, corporate financing, and equipment processing for installing early telephone service, as well as the challenges faced by suppliers of equipment used in said process.

MCI Communications Corporation (MCI) was a large telecommunications company. It was organized in October 1963 in Joliet, Illinois, by John D. (Jack) Goeken (1930-2010), as Microwave Communications, Inc. Goeken and his partners were planning to provide point-to-point private line microwave communications between Chicago and St. Louis to small businesses. This large collection documents the activities of the MCI Communications Corporation and its subsidiaries as well as the development of a competitive telecommunications industry in the United States and worldwide. The materials focus on MCI corporate life, public relations, technical operations, and sales and marketing activities. A vast amount of videotapes makes up a significant portion of the MCI collection, however, there are also photographs, slides, digital files, and audio cassette tapes.

MCI Communications Corporation (MCI) was one of the largest telecommunications companies in the world. It was incorporated in Delaware in 1968 as Microwave Communications of America, Inc., to provide businesses with nationwide microwave telecommunications services at low prices. Being confronted by industry de facto monopoly AT&T in the interconnection of its lines to local facilities owned by AT&T affiliated regional Bell companies, MCI challenged the telecommunications giant with competitive long-distance telephone services, both in courts and at the marketplace. MCI-AT&T antitrust litigation (1974-1985) led to AT&T's divestiture of its regional carriers and changed the previously regulated telecommunications industry into a business open to competition. The collection documents all facets of MCI history from 1968 to the end of the 1990s, as well as changes in the American telecommunications regulatory policy, legislation, and public perception of the industry. Documents also include records of MCI's subsidiaries and their predecessors starting as early as 1849.