We live in an era of unprecedented medial access to other scales, thanks to advances in digitization, big data, probe microscopy, distributed telescopic arrays, satellite imaging, screen technologies, and visualization techniques. To what extent have the protocols, assumptions, and affordances of these technologies shaped what we can and cannot see when we access the scales they make available? This dissertation examines an explosion of "scalar media" in the late twentieth and early twenty-first centuries, from early "cosmic zoom" books and films to the current media ecologies of nanotechnology and geoengineering, and asks what role they play in our discursive framings of ecology, technoscience, and the human. Instead of relying upon conventional understandings of scale to characterize the relationships between human and non-human entities, the focus of this study is on the conjoined cultural and material processes that divide phenomena into discrete scales and differentiate matter into new assemblages at new scales. Scale, then, has two faces: On one hand it delimits a theater of action for a given individual or collective subject---determining which objects take on meaning within that subject's milieu---and on the other, scale "pushes back" in the form of nonhuman entities that exhibit non-continuous, scale-sensitive properties that irrupt our implicit notions of a continuum underlying the forces of nature or culture. Thus scale mediates between the assertions of material assemblages and the assertions of categorical thought. The great crises of the Anthropocene---global climate change, pollution, species extinction, human overpopulation, ocean acidification, and the displacement of climate refugees, among others---all play out at this defamiliarizing intersection between scalar access and scalar alterity. Within this circuit of mediation our multi-scalar environments are reduced and framed into signifying milieus.

As an interdisciplinary work of scholarship, this dissertation discusses cosmic zoom books and films, literary works from the eighteenth century to the present dealing fundamentally with issues of scale and identity, philosophical texts from Democritus onward, popular speculative fiction dealing with nanotechnology, amateur documentary and online media, and theoretical texts in the fields of the environmental humanities, science and technology studies, media studies, and literary studies.

By engaging and accounting for scale as both a primary form of differentiation external to the human and as an arbitrary set of size domains generated through disciplinary knowledge production, this dissertation hopes to expand both our operative definition of "scale" and our understanding of media to embrace the processes by which new forms are generated in both the material and discursive domains of our milieu. This study thus argues that any attempt to produce a resilient future-oriented ecology must also engage the production of new, trans-scalar subjectivities, and vice versa. (Abstract shortened by UMI.).