This collection contains the technical and professional documents of consulting engineer Blair Birdsall. Most of the collection are documents pertaining to the multitude of bridges he worked on, including the Golden Gate, Chesapeake Bay, and Brooklyn Bridges, as a consulting engineer or as a design engineer. The collection spans from 1900 to 2002 covering his entire career and also early Steinman Boynton Gronquist & Birdsall and John A. Roebling Sons Engineering companies.

Materials on Bethlehem Steel (including ephemera, catalogs, technical reports and drawings), Lehigh University (brochures, reports, Alumni Association publications); publications on manufacturing of steel and steel products, Pennsylvania and Lehigh Valley municipal maps compiled by Charles R. Nippert, Lehigh Class of 1947, a mechanical engineer at Bethlehem Steel Corporation.