In this paper, I explore the environmental philosophy of three Californian modernists, who I have collectively named the Dust Dwellers: John Steinbeck, Robinson Jeffers, and Jack London. I argue that these writers participated in a broader modernist response to the ascendancy of the Enlightenment and its manifestation in industrial progress. Furthermore, I demonstrate that the Dust Dwellers' response was distinctly informed by their American identity. They engaged modernist themes of decay as applied to Western expansion and the dissolution of the American Edenic dream. Investigating the fractured relationship between civilization and the environment, they searched for a philosophy that could reconcile humanity to nature. Specifically, I argue that their environmental philosophy displays intellectual and creative congruencies that can be traced to the common influence of twentieth-century psychoanalyst Carl Jung. The foundational tenet of the Dust Dwellers' environmental philosophy parallels Jung's concept of the unus mundus. Mirroring Jung's interpretation of this alchemic term, the Dust Dwellers describe a cosmic unity that encompasses all of life. I discuss depictions of the unus mundus across the Dust Dwellers' work and outline other implications of this central philosophic presupposition. Ultimately, I conclude that their environmental philosophy, along with other attributes, permits and even encourages scholars to approach these writers as a distinct group of American modernists. / Master of Arts / In this paper, I explore the environmental philosophy of three Californian modernists, who I have collectively named the Dust Dwellers: John Steinbeck, Robinson Jeffers, and Jack London. I argue that these writers participated in a broader modernist response to the Enlightenment's failed pursuit of utopia. Furthermore, I demonstrate that the Dust Dwellers' response was distinctly informed by their American identity. They engaged modernist themes of decay as applied to the American frontier. Specifically, they recognized that America had failed to transform into a new Garden of Eden. Investigating the negative effects of industrial civilization, the Dust Dwellers searched for a philosophy that could create harmony between humanity and nature. I argue that their environmental philosophy displays intellectual and creative congruencies that can be traced to the common influence of twentieth-century psychoanalyst Carl Jung. The foundational concept of the Dust Dwellers' environmental philosophy parallels the Jungian concept of the unus mundus. Mirroring Jung's interpretation of this alchemic term, the Dust Dwellers describe a cosmic unity that encompasses all of life. I discuss depictions of the unus mundus across the Dust Dwellers' work and outline other implications of this central philosophic presupposition. Ultimately, I conclude that their environmental philosophy, along with other attributes, permits and even encourages scholars to approach these writers as a distinct group of American modernists.