Columbia subject headings:
Architecture--Illinois--Chicago--History--20th century.
Chicago (Ill.)--Guidebooks.
Commercial buildings--Illinois--Chicago.
Office buildings--Illinois--Chicago.
Harvard subject headings:
Architecture, Modern--20th century--Illinois--Chicago--Guidebooks.
Architecture--Illinois--Illinois--Chicago--History--Guidebooks.
Chicago (Ill.)--Architecture--Guidebooks.
Chicago (Ill.)--Buildings, structures, etc.--Guidebooks.
Skyscrapers--Illinois--Chicago.
Princeton subject headings:
Architecture, Modern--20th century--Illinois--Chicago.
Architecture--Illinois--Chicago--Guidebooks.
Chicago (Ill.)--Buildings, structures, etc.--Guidebooks.
Guidebooks.