Life is not necessarily easy, and certainly not predictable, for the inhabitants of the várzea. An analysis of the variables that determine their dynamic adaptation to the diversity implicit in the várzea´s aquatic and terrestrial ecosystems requires both an interdisciplinary and an historical approach. Four of the chapters in this section of the book look at external factors that challenge livelihood strategies and daily living patterns for families in the várzea communities: Harris looks at historic processes that formed modern várzea societies, Benatti at the uncertainties inherent to the tenure system for land and resources, Alencar at the impact of federal and state policy or lack thereof, and Silva at the effect of all these uncertainties and changes on the health of the ribereño population. On the other hand, in the fifth chapter, Costa and Brondízio remind us that the Brazilian Amazon region, and in particular the várzea, has been for a long time an “urbanized forest,” thus adding a relatively new angle to our look at Amazonian floodplain societies. Each perspective contributes to our picture of the dynamic and uncertain nature of human life in the várzea.