Supraregional investigations of the Holocene occupational history of the eastern Sahara west of the Nile combined with the study of climatic, environmental, and geomorphological archives were carried out in contrasting desert regions from the Mediterranean coast strip to Wadi Howar in Sudan. The research areas are located far away from groundwater influence and are therefore capable of indicating environmental changes. Climatic development in accordance with nearly 500 14C dates from archaeological sites indicates a Holocene optimum lasting from approximately 9500 B.P. till the beginning of the drying trend that set in about 6300 B.P. (9000–5300 cal. B.C.). Although the faunal and floral remains are arid types, they indicate slightly wetter conditions than today. Surface water was the key factor that influenced the adaptation strategies of the mobile hunter-gatherers (and in some parts, the pastoralists) in the desert regions. Large episodic camp sites agglomerated at favorable drainage systems and water pools, and settlement patterns strongly correlate with the paleohydrological factors examined with remote sensing cartography, geomorphological work, and the analysis of digital elevation models. © 2007 Wiley Periodicals, Inc.