This chapter lays out the case for a new guiding paradigm to shape further theoretical development of strategic management—defined broadly as the study of behavior and performance of profit-seeking firms—as a science of corporate life. A new paradigm in turn requires a clear understanding of the ontological foundations of theories within the current paradigm of sustainable competitive advantage and the ontological issues that motivate its replacement. The ontological foundations of extant theories in strategic management remain inadequate as axiomatic foundations for theories that intend to focus on the dynamics of strategic firm behavior in dynamic competitive environments. The conceptualization of dynamic strategy, like other theoretical endeavors, must focus on two distinct albeit related issues: (a) description of reality and (b) tools for analysis. The bimodal reality of evolutionary ontology, which maintains a dichotomy between the cognitive world (i.e., subject world) and the real world (i.e., object world), seems to be the natural position for the field of strategic management. What are the implications of adopting an evolutionary ontology for theorizing about the dynamics of strategy? This chapter explicates the paradigmatic-ontological foundations of a descriptive theory of dynamic strategy and the accompanying analytical framework, Evolutionary Strategy Dynamics (ESD). The choice of evolutionary ontology determines the: (a) framework for the conceptual elements of the [evolutionary] theory of dynamic strategy and (b) epistemology for the boundary conditions of the [evolutionary] theory of dynamic strategy.