Architect Louis Sullivan

The lobby of the Auditorium Hotel inside the Auditorium Building, with its doors facing east onto Michigan Avenue, circa 1908. The building was built in 1889 by Dankmar Adler and Louis Sullivan. (Chicago Tribune historical photo)

Louis Sullivan, often called the “father of skyscrapers” and mentor to Frank Lloyd Wright, reshaped Chicago architecture by emphasizing form that follows function, pioneering tall building design with steel-frame construction, expansive windows, and simplified massing while integrating richly ornamented, organic terra-cotta detailing; his work—most notably the Auditorium Building and the Carson, Pirie, Scott department store—helped define the Chicago School’s pragmatic approach to urban commercial architecture, influenced the rise of modernism by rejecting historicist pastiche, and left a legacy of structural honesty and decorative restraint that continues to inform contemporary high‑rise design and preservation efforts in the city. Whenever Wright came to Chicago from Taliesin, his Wisconsin studio, he would visit Sullivan. “Lieber Meister,” he called him, beloved master.