The work of Manoel de Barros holds a unique place in contemporary Brazilian literature, offering a poetic journey through the Pantanal. This thesis explores Barros' Primitivist Poetic System, a set of poetic principles and practices that structure his work. Using Livro de pré-coisas as the object of study, the interdependence between time, space, and characters is observed, along with a symbiosis between memory and imagination. Based on the philosophy of Giambattista Vico, who views poetry as a primitive form of language, this analysis examines how Barros employs these elements to recreate a mythical and timeless natural world. In the first chapter, primitivism in Barros' work is defined, addressing its relationship with nature. The second chapter develops the concept of the Primitivist Poetic System, grounded in Vico's ideas. The third chapter focuses on Livro de pré-coisas and the figure of Bernardo da Mata, the poet's alter ego, who synthesizes the unity between man and nature. The conclusion suggests that Barros' poetry, permeated by his life experiences, functions as a form of autofiction, celebrating language, memory, and imagination, and proposing a new way of inhabiting and interacting with the world. Keywords: Manoel de Barros; Primitivist Poetic System; Livro de pré-coisas.