A brief biography is given of Alexander Tornquist (1868–1944), professor of geology (and related subjects) successively in Strassburg (now Strasbourg), Königsberg in Preussen (now Kaliningrad) and Graz. He was not the first scientist to detect the lineament marking the south-western border of the East European (Russian) Platform, but his was nevertheless a pioneer effort in synthesizing the local studies to illustrate the major importance of the feature in the regional geology of Europe, presenting it in the international literature of his time. Hence, it has been referred to by subsequent authors, widely and with justification, as the ‘Tornquist Line’.Project Tornquisthas been the prescribed key title for the IGCP project, whose full title isEast European Platform (south-western border).