This thesis studies the transition between Decadent and Modernist poetry in England. The general critical perspectives of the evolution between the fin-de-siècle poetry of the 1890s and the high-Modernist verse of the 1920s were either of too great a separation, or too much a continuation. This study suggests that the Decadents were in fact precursors of the Modernists in their attempts to both stylistically and substantively challenge the dominant modes of poetry, its publication, and its relationship with the reading public in the face of the continued and exponential growth of industrialization, urbanization, commercialization, and other perceived consequences of modernity. For reasons such as the resistance of Victorian morality, the perception of corrupted ideals, belief in influence from the Continent, and the relative disorganization and self-destructive tendencies of its figures, the Decadent poets were largely unable to realize their goal of restructuring poetry and challenging the superiority of modernity. The groundwork they did, however, allowed the Modernist poets who were to become well-known thirty years later to make the revolutionary changes that garnered the Modernist movement the critical and populist importance it had contemporaneously and still has today. Through a mixture of historical and formalist criticism, this thesis attempts to define briefly both Decadent and the Modernist poetry, and trace the transition between the two literary eras. It looks closely at many of the dominant figures in each movement, and links them together within three significant themes that they shared: alienation, disintegration, and reconstruction.