The dynamics of Epipalaeolithic and Early Neolithic adaptations in the southern Levant from areas west of the Rift Valley are briefly described and evaluated against the backdrop of climatic changes. Taking account of recent advances in environmental studies and important revisions in the chronological framework of pollen diagrams from the Hula, a high degree of correlation between environmental and cultural developments is apparent. The variable nature of environmental changes and the mosaic of ecological zonation on human adaptive systems are stressed, with differentiation between : long-term incremental trends; sudden climatic changes; and predictable annual fluctuations about a mean. The nature and flexibility of the responses by communities to such external changes depended upon specific combinations of technological, social and ideological, psychological as well as idiosyncratic factors. Favourable niches alternately expanded or contracted. At times human adaptation systems in Cisjordan can be divided into two provinces, Mediterranean and Steppe/Desert ; at other times they included adjacent areas, such as Transjordan and the northern part of the Levantine corridor. A number of crises or "bottle-neck" situations, most resulting from environmental changes, are described which caused radical re-alignments in social and subsistence systems. It is against this backdrop, together with generally conservative social systems, that the transformation from foraging to plant and animal husbandry should be viewed.