Central Asia combines two geocultural domains, steppes and oases, emphasizing two lifestyles. Our multidisciplinary researches, based on international cooperation, intend to explore major historical topics on a broad chronological and geographical scale, including the study of the evolution of fragile ecosystems. The study of two desert areas (Kyzyl-Kum in Uzbekistan, Taklamakan in Xinjiang, China) exemplify our approach: to test in Xinjiang the hypothesis of the existence of ancient agricultural settlements, and to examine in Uzbekistan the hunter-gathererfisher societies on the way to neolithisation, to understand their variety and evolution in nowadays totally dry deltas, and to clarify settlement patterns over the long term (from Neolithic to Antiquity). Archaeological sites discovered by our fieldwork give some clues about cultural patterns, subsistence practices, irrigation systems, and social organization from nomadic to sedentary systems. Our results tend to reconstruct modalities of the interactions between man and the environment in an unstable context, and to illuminate constants and variables of change in local, regional, and “international” scales.