Research background　
　 Up to date, nomadic societies have been considered as the opponents against urban societies, pulling triggers to destroy civilizations.   .
　 It is well known, for example, that the 3rd dynasty of Ur of the 2nd Millennium B. C. southern Mesoptamia was destroyed by the semitic nomadic tribes and the nomadic Huns of East-Central Asia and the Qin/Han dynasties of China were struggling each other around the beginning of the Christian era.
　 The views to oppose the nomadic societies against the urban societies, however, were created by the latter societies who invented inscribed letters.
　 The members of the present research undertook excavations in the Bishri Mountains near the city of Raqqa, North-East Syria, in order to know how the “Amorite nomadic societies” of the region were leading their lives in the period around 2000 B. C.
　 After the excavations, several fruitful results were yielded, strongly suggesting that the “Amorite” people were 1) practicing griculture and sheep herding at the same time, 2) flexible enough to separate their societies into agriculturists, nomads and citizens and to re-unite them in accordance to external causes such as the changes of climate, and 3) mediators in the commerce at trading posts along the rivers.
　 These results not only demonstrated the variations of the founders of the city-based civilizations of West Asia, but also showd that the research of the developments of nomadic societies would be also valid in the research of the developments of human societies.
　 In these views, we planned a project to be carried out in the Eurasian arid region, which is wider than West Asia and includes West Asia and Central Asia, and selected Kyrgyzstan as the region for a comparative research, taking advantage of our field-work experiences in West Asia.