The art historian Alois Riegl (1858–1905) is today considered one of the intellectual leaders of the Viennese fin de siècle. His writings, which enjoy international acclaim, represent a new and in part radical direction in his field. Riegl served as curator at the Austrian Museum for Art and Industry (today the MAK) as well as full professor at the University of Vienna, and finally as the General Conservator for the Central Commission for the Research and Preservation of Art and Historical Monuments. In all these functions Riegl explored new paths of art research, the innovative nature of which has only recently been recognised. On the occasion of the centenary of his death, a symposium was held in late autumn 2005, attended by highly regarded experts whose contributions – sometimes in greatly extended form – have been collected in the present volume. Not only do they illustrate the immense range of Riegl’s ideas, they also shed light on the intellectual contribution made by the Viennese art historian to European modernity.