The history of this region and its people has been developed chiefly through the genius of French archæologists, beginning with Boucher de Perthes. The more recent discoveries, which have come in rapid and almost bewildering succession since the foundation of the _Institut de Paléontologie humaine_, have been treated in a number of works recently published by some of the experienced archæologists of England, France, and Germany. I refer especially to the _Prehistoric Times_ of Lord Avebury, to the _Ancient Hunters_ of Professor Sollas, to _Der Mensch der Vorzeit_ of Professor Obermaier, and to _Die diluviale Vorzeit Deutschlands_ of Doctor R. R. Schmidt. Thus, on receiving the invitation from President Wheeler to lecture upon this subject before the University of California, I hesitated from the feeling that it would be difficult to say anything which had not been already as well or better said. On further reflection, however, I accepted the invitation with the purpose of attempting to give this great subject a more strictly historical or chronological treatment than it had previously received within the limits of a popular work in our own language, also to connect the environment, the animal and human life, and the art. This element of the _time_ in which the various events occurred can only be drawn from a great variety of sources, from the simultaneous consideration of the geography, climate, plants and animals, the mental and bodily development of the various races, and the industries and arts which reflect the relations between the mind and the environment. In more technical terms, I have undertaken in these lectures to make a synthesis of the results of geology, palæontology, anthropology, and archæology, a correlation of environmental and of human events in the European Ice Age. Such a synthesis was begun many years ago in the preparation of my _Age of Mammals_, but could not be completed until I had gone over the territory myself.