This dissertation investigates the way in which the geographical condition of insularity has been represented in Puerto Rican literature of the twentieth century. The central idea is what I call the “poetics of the island”, using the term “poetics” in the etymological sense of poiesis, “to create” or “to make”. The “poetics of the island” asserts that in the case of Puerto Rican literature, insularity is not an absolute, priori space but rather a phenomenon that is discursively produced by authors of differing sociocultural and ideological positions. Throughout the twentieth century, intellectuals and poets in Puerto Rico have turned to the figure of the island in their texts to confront pressing cultural, economic, and political questions. By doing so, they have produced widely varying accounts of Puerto Rico’s history, the present circumstances in which they found themselves, and its future. Recurrently, these different poetics of the island have been marshalled to examine, and often propose explicit solutions to, one of Puerto Rico’s most intractable issues, that of its relationship to the United States. That link is predicated on the juridical status of “non-incorporated territory”, which makes the island a possession of the United States without formally belonging to it, a dynamic that has produced a host of political and socioeconomic problems for Puerto Rico and its people. I analyze the dialogue that literary representations of insularity establish with the fact of “non-incorporation”, as well as with other important concerns, through texts that develop a gamut of ideological and cultural perspectives with respect to Puerto Rico’s internal and external affairs. I begin with Antonio Pedreira’s essay Insularismo: Ensayos de interpretación puertorriqueña (1934), move on to María Zambrano’s essay Isla de Puerto Rico: Nostalgia y esperanza de un mundo mejor (1940) and Juan Ramón Jiménez’s heterogenous Isla de la simpatía (1981), pass through to Francisco Matos Paoli’s poetic work Luz de los héroes (1954), and end with José Luis González’s essay “El país de cuatro pisos” (1979) and novel La llegada (1980). The most fundamental idea in this dissertation is that both the “non-incorporporated territory” and the literary response to it form conditions of possibility for imagining what Puerto Rican culture and society can and should be, at times overlapping and other times conflicting sharply. The historical frame covers roughly forty-five years, from the mid-1930s to the late 1970s, when Puerto Rico experienced a number of socioeconomic and political crises that were intimately related to its status as a “non-incorporated territory”. It is in these moments that influential literary texts have used the figure of the island in order to imagine a path through the many problems that arise before Puerto Rican society.