This chapter describes some of the principal physical aspects of California in relation to the life and civilization of the region. The task is at once comparatively simple and hopelessly complex. The topography of the Pacific slope is in certain of its principal features extremely easy to characterize. However, closer study shows how difficult it is to understand the relation of precisely such features to the life that has grown up in this region. The principal interest of the task lies in the fact that it is the American character and civilization which have been already molded in new ways by these novel aspects of the far western regions. In endeavoring to distinguish between what has resulted from physical conditions and what has been due to personal character, deliberate choice, general national temperament, or pure accident, one is dealing with a task for which the data are insufficient.