Architects:  Louis Sullivan, 1899;  Twelve story south addition, D. H. Burnham and Company, 1903-4; Eighth story south addition, Holabird and Roche, 1906?  Designated a Chicago Landmark in 1970.   The store closed in 2007, and in 2010 is being remodeled as mixed-use retail/office space ("Sullivan Center"). Thanks, Nora Tocus for this information.