In this study, I will present some documentary evidence that Carlos Drummond de Andrade’s poem “A Máquina do Mundo” [The Machine of the World] (1949) was based on prior reflections contained in a forgotten newspaper article entitled “Poesia e Pesadelo” [Poetry and Nightmare] (1949). In that article, Drummond critically analyzed some of the theses of Stephen Spender's essay “What Is Modern in Modern Poetry” (1948), which had just been published in The Tiger's Eye magazine. As soon as he read Spender's text, Drummond wrote “Poetry and Nightmare” and began to elaborate a narrative poem whose protagonist would be a machine. All the documentary evidence indicates that Drummond took Spender's lessons as touchstones for the elaboration of the narrative and allegorical structure of “The Machine of the World.” According to the interpretation I am proposing here, Drummond, in writing the machine poem, put into practice at least six lessons drawn from Spender’s essay, namely: 1) the modern poet must represent the tension between the external machinelike landscape and the landscape of the inner world of the creative imagination; 2) he must also represent the machinelike, ugly, and urban world around him in a beautiful and poetic way; 3) he must avoid the misconceptions of excessive utopian visionarism, as well as creeping realism; 4) he must reject the imperative of political engagement, whose principle of action states that poetry has a transformative mission in society; 5) he must free himself from the obsession with free verse as the only form of modern poetry and start using the traditional fixed forms; 6) he must understand machines as poetic symbols of human passions, and not just as exotic objects foreign to human reality. My conclusion is that, after reading Spender’s essay, Drummond changed his aesthetic and philosophical understanding of what defines the essence of modern poetry, both in terms of form and content.