What accounts for the spectacular success of contemporary genetics and allied sciences? The usual explanation of scientific success is theory-focused. It assumes that investigation is based on a core theory that grasps the fundamentals underlying the domain of phenomena being investigated. Waters is developing an alternative explanation that draws attention to concrete descriptive knowledge, procedural knowledge, and research strategies. These elements are integrated with modest theoretical knowledge to form what he calls an investigative matrix. According to this practice-centered epistemology, an investigative matrix can be used to systematically investigate phenomena that are not explained, even potentially explained, by the modest theoretical knowledge upon which the research depends. On this view, the success of a mature science need not be based on theoretical knowledge of the fundamentals. Instead, it can be based on investigative strategies that presuppose a modest theory of limited aspects of the domain being investigated. In this talk, Waters will show that the theoretical basis of success in contemporary genetics and molecular biology can be understood in this way.