This dissertation examines the role of popular texts, public lectures, and other forms of non-technical communication in Austrian natural science between 1865 and 1916. Its argument is threefold. First, that a loosely affiliated group of biologists, naturalists, and physicists not only used their popular work to disseminate basic facts about their research to laypersons but to intervene in ongoing scientific discussions, ranging from debates over minor technical matters to controversies that concerned the natural sciences as a whole. Second, that this group understood the scientific value of their popular interventions to be a function of their capacity to mediate between the experiential and intellectual world of the “average man” and that of the professional researcher. For example: the physicist Ernst Mach held that articulating the “substantial sameness of scientific and every-day thought” in his popular corpus was a means of convincing his colleagues that physical concepts and laws emerged from the same biological processes that governed every other aspect of organic life. Botanists Richard von Wettstein and August Ginzberger approached the genre with slightly different aims in mind, using their popular texts and lectures to shape scientific debate about controversial topics like natural selection and to enlist amateur collectors and observers into their research projects. But the common denominator in both cases was a belief that the lay public was not just a source of error and superstition to be disciplined but a resource which popularization could mobilize for scientific ends. And third, this dissertation argues that the Austrians’ belief in the epistemic salience of the “everyday” was closely tied to the conceptual and institutional transformation of scientific inquiry over the latter half of the nineteenth century, as well as the idiosyncratic development of scientific life in the Habsburg Monarchy after 1848.