His `` habilitation '' work was entitled '' '' ( published in English translation in 1989 as `` The Structural Transformation of the Public Sphere : an Inquiry into a Category of Bourgeois Society '' ) .
His `` habilitation '' work was entitled , `` Strukturwandel der Öffentlichkeit ; Untersuchungen zu einer Kategorie der Bürgerlichen Gesellschaft '' ( published in English in 1989 titled `` The Structural Transformation of the Public Sphere : an Inquiry into a Category of Bourgeois Society '' ) .