This volume presents the results of the excavations carried out between 1960 and 1974 at `Ubeidiya. The site, located in the Dead Sea Rift, is composed of more than sixty archaeological horizons of Lower Pleistocene age (1.4 million years). The site reveals a complex geological structure in which tectonic movements have drastically tilted the deposits. The cultural remains are assigned to the Acheulian tradition, the earliest known manifestation of this industry outside Africa. Each archaeological horizon is described, and its lithic assemblages are presented in detail. Their typological, technical and stylistic characteristics are studies by means of attribute analysis. The analysis of the stone artifacts has important implications for the reconstruction of hominid behavior. The issue of the distinctive "living floors" is discussed and various interpretations of their formation, whether due to human or natural agencies, are offered. The unique importance of `Ubeidiya lies in the fact that it is the best-documented site in Eurasia that illustrates the spread of humankind from Africa into the rest of the world.