This interdisciplinary dissertation proposes and explores the concept of "psychonautic media." From the Greek roots psyche (mind, soul) and nautes (sailor, navigator), "psychonautic(s)" refers to both the subjective experience of altered states of consciousness, and the fields of research founded on such states. Psychonautic media therefore includes any object, substance, environment, etc. used to alter consciousness and perception. Unlike other forms of media, psychonautic media are thus defined not by their physical format or technological function, but by the unique nature of their "content"---the production of altered states as "inner media" experiences---"images" constituted by a shift in perception itself (in how the subject perceives). Within this speculative framework, I present a series of experimental case studies---on LSD, the wilderness, and sensory deprivation---that focus in particular on the relationship between subjectivity, perceptual experience, and various forms and processes of mediation (material, linguistic, ideological, etc.). Grounded in a "horizontal" methodology, and constituted by conceptual and aesthetic montage, each study integrates personal narrative; interpretations of concepts from psychoanalysis, philosophy, and literary theory; descriptions, histories, and analyses; and imagery and graphic text. Situated between art and scholarship, my aim for this project is twofold: to invent and enact, theorize and embody, the concept of psychonautic media; and, in so doing, to model an alternative mode of thinking about and doing research.