View of air ducts in penthouse, South Wing, Main Library, Detroit Public Library during construction. Stairway door to penthouse on right. Handwritten on front: "Unit S2, stair #13." Printed on front: "Detroit Library Commission. Addns & alterations to Main Public Library. Bryant & Detwiler Company, contr. Descr. penthouse, S. Wing. No. 123. Date: 12-27-61. Win Brunner, photo."
