Bacteria thrive in a limitless range of extreme environments, accompanied by exotic metabolisms and rather sophisticated behaviors.  Despite this tremendous diversity, our modern molecular understanding of bacteria comes from studies of a limited range of phenotypes in a handful of model organisms.  Furthermore, studies of microbial physiology in model systems such as E. coli have historically focused on a set of environmental conditions defined more by convenience of laboratory growth and preconceived notions of nutrition and stress, rather than ecologically relevant environments and transitions. These laboratory conditions and the corresponding behavioral responses under-estimate the complexity of bacterial behavior in their ecologically native niche.  We have developed experimental methods and conceptual frameworks that rapidly and comprehensively reveal the molecular underpinnings of diverse bacterial behaviors across the microbial biosphere.  Our approaches utilize global measurements of gene expression, protein-DNA interactions, and fitness, in order to understand how systems-level molecular behaviors allow microbes to thrive in dynamic and competitive multi-species environments.