The book summarizes the results of twenty years (1983-2003) of research in the field of Stone Age archeology carried out by the author as part of the Soviet-Yemeni (since 1992 Russian) expedition in the Republic of Yemen. During this time, more than a hundred Paleolithic, Neolithic and post-Neolithic sites have been identified and investigated. Unique among them are the Oldovan monuments, revealing a new aspect of the problems regarding the time and ways of the initial settlement of man from his ancestral home - East Africa - to the Asian continent.