Archibald Johnston (1864-1948) was a mechanical engineer, who joined the Bethlehem Iron Company in 1889 where he was responsible for the erection of the gun forging and armor plate plant. In 1901 he was elected to the company's Board of Directors, and between 1906 and 1908 was president of the Bethlehem Steel Corporation. The bulk of this collection is concerned with Johnston's work at Bethlehem Steel; a smaller portion consists of strictly personal papers.

George A. Richardson (1886-1976) was an engineer with an expertise in metallurgy. He spent his career primarily involved in technical publicity and sales for major steel manufacturers such as the Midvale Steel & Ordnance Company and the Bethlehem Steel Corporation. The papers consist primarily of materials collected by Richardson during the performance of his official duties with the steel companies, in preparing technical lectures and papers, and in teaching courses in metallurgy.

George A. Richardson (1886-1976) was an engineer with an expertise in metallurgy, he spent his career primarily involved in technical publicity and sales for major steel manufacturers such as the Midvale Steel & Ordnance Company and the Bethlehem Steel Corporation. This collection of photographs and negatives was primarily taken by George Atwell Richardson throughout the course of his career while working for Midvale Steel and Ordnance Company and the Bethlehem Steel Corporation. The images document views of steel plants and operations, as well as steel products mostly taken between 1913 and 1929. The collection has been organized into five series: Midvale Steel and Ordnance Company; Cambrian Steel Company; Bethlehem Steel Corporation; Exhibits, and Other steel and coal companies.

Maryland Steel Company was a steel-works and shipyard operated from 1891 until 1916, when Bethlehem Steel acquired the Pennsylvania Steel Company and its subsidiary, Maryland Steel. This collection consists of 3 albums containing 204 cyanotype photographs taken at the Maryland Steel Company's steel plant and shipyard between 1890 and 1894. The photographs show steel buildings, steel workers, shipyard buildings, ship construction, tugs and steamships.

William M. Henderson (1831-1904) was a mechanical engineer and inventor who spent most of his career in Philadelphia. The papers consist of two items: a scrapbook, which pertains to Henderson's career and inventions, and an atlas of twenty-nine plates of Bessemer and rolling-mill machinery.