For most of the twentieth century, modernist viewers dismissed the architectural ornament of Louis H. Sullivan (1856-1924) and the majority of his theoretical writings as emotional outbursts of an outmoded romanticism. In this study, Lauren Weingarden reveals Sullivan's eloquent articulation of nineteenth-century romantic practices - literary, linguistic, aesthetic, spiritual, and nationalistic - and thus rescues Sullivan and his legacy from the narrow role imposed on him as a pioneer of twentieth-century modernism. Using three interpretive models, discourse theory, poststructural semiotic analysis, and a pragmatic concept of sign-functions, she restores the integrity of Sullivan's artistic choices and his historical position as a culminating figure within nineteenth-century romanticism.By giving equal weight to Louis Sullivan's writings and designs, Weingarden shows how he translated both Ruskin's tenets of Gothic naturalism and Whitman's poetry of the American landscape into elemental structural forms and organic ornamentation. Viewed as a site where various romantic discourses converged, Sullivan's oeuvre demands a cross-disciplinary exploration of each discursive practice, and its 'rules of accumulation, exclusion, reactivation'. The overarching theme of this study is the interrogation and restitution of those Foucauldian rules that enabled Sullivan to articulate architecture as a pictorial mode of landscape art, which he considered co-equal with the spiritual and didactic functions of landscape poetry.