An interest in the concept of ornament, and in the range of artistic practices traditionally called ornamental, has long been recognized as a feature of the literary and artistic culture of the Viennese fin de siècle, also called Jugendstil. In my interdisciplinary dissertation I argue that we can speak of a foundational epistemological structure aptly described as “ornamental structure,” which finds expression in poetry and drama, in aesthetics and art historical inquiry, in political thought, and, indeed, in psychoanalysis. Ornament addresses a central issue of philosophy, namely the relationship between matter and form or, put differently, between depth and surface, which is rethought in a fundamental way in the second half of the 19th century. In Chapter One, I show how the concept of ornament first entered scientific and philosophical debates with the emergence of aesthetics as an academic field in the 18th century. The chapter traces its history from this first appearance up to its revaluation in mid-19th century. I show that ornament had always had a liminal and ambiguous place within aesthetic thought. I do so by exploring the role of ornament in changes in both the life sciences and art history, making use of the examples of the evolutionary biologist Ernst Haeckel and the art historian Alois Riegl. Ornaments come to be considered as creative since they are thought to highlight the movement, variation, and creation of life itself in a way that depicts life by abstracting from natural phenomena. They, thus, are more than just a matter of taste or regalia. I argue that we see here the emergence of a new epistemological structure, one which throws light on the relationship between art and life at the end of the 19th century. In Chapter Two, I investigate this altered understanding of the relationship between art and life in a discussion of Hofmannsthal’s lyric drama The Death of Titian (1892), one of the first examples of Jugendstil literature in the Austro-Hungarian context. The second part of this chapter investigates the role ornament plays for Vienna’s artists who break with historicism in the Viennese Secession movement. Chapter Three addresses early 20th century representations of the psyche. It explores ornamental narrative strategies in Hugo von Hofmannsthal’s Hofmannsthal’s Märchen der 672. Nacht (Fairytale of the 672th night ) and Sigmund Freud’s Interpretation of Dreams (1900). I investigate the ways in which the understanding of unconscious desire as a labyrinth ornamental surface structure is a central concept for psychoanalysis. Chapter Four explores a set of narrative and cultural strategies that, in the wake of the collapse of the Austro-Hungarian empire, seek to reimagine the community of Habsburgian subjects after the end of the monarchy. In my analysis of Hofmannsthal’s tragic drama Der Turm (The Tower [1925/27]) I show that the dichotomy of the monarch’s two bodies is replaced by the monist model of what I come to call, the “king’s ornamental body”, which is imagined to overcome the split between a cultural body and the — no longer existing — physical body of the monarch. By heightening awareness of how the dualism of life and form is replaced by an aesthetic monism in the epistemological structure of ornament, my dissertation places the work of Hugo von Hofmannsthal within the context of a series of broader changes in art, the natural sciences, discourses on the psyche, and the aesthetic-political sphere. The project seeks to form a valuable interdisciplinary link between fields such as Austrian/Habsburg studies, literature and art history, interart studies as well as 19th and 20th century investigations of aesthetic theory and intellectual history.