The last twelve years have seen a new impetus given to prehistoric studies by the multiplication of researches outside Europe. Excavations in Africa, the Near East, Asiatic Russia and China have opened up a new field for speculation, and at the same time have revealed the unsuspected complexity of many problems which to De Mortillet and other pioneers seemed relatively simple. Gone for ever is the straightforward succession of Palaeolithic cultures from Chellian to Magdalenian as laid down in the Musée Préhistorique. Even as early as 1912, when Breuil produced his classic paper on the subdivisions of the Upper Palaeolithic its foundations were sapped, and the discoveries of the last decade have merely completed its demolition as a system of world-wide application.I need not insist that De Mortillet's scheme, as corrected by Breuil, who first pointed out the true position of the Aurignacian in western Europe, was the best that could be devised given the very incomplete information, relating to a very limited area, possessed by workers at that date. The fault of De Mortillet's disciples lay in their canonisation of a system which could only be applied locally, and which in any case contained enormous gaps.