At Penn, Aaron regularly teaches four courses in the Preservation Program: a survey of American architecture, a seminar on the same topic, and two courses on the documentation of historic sites. His scholarship focuses on nineteenth-century American architecture and urbanism. Special interests include: antebellum suburbs and cemeteries, infrastructure and industrial architecture, Quaker aesthetics, and the politics of commemoration. He serves as vice president of Philadelphia’s Woodlands Cemetery and has been active on other nonprofit boards. His preservation advocacy work has received various forms of recognition, includinh the Preservation Alliance for Greater Philadelphia’s Public Service Award for Preservation in the Public Interest, shared with Mayor Wilson Goode, Sr., in 2015.