Interior view of penthouse, North Wing, Main Library, Detroit Public Library under construction. Construction materials and equipment in room; pipes and ductwork overhead. Handwritten on front: "North penthouse, 186.20 elev." Printed on front: "Detroit Library Commission. Addns & alterations to Main Public Library. Bryant & Detwiler Company, contr. Descr. n. penthouse. No. 183. Date: Jul 19, 1962. Win Brunner, photo."