Though incomplete, the essay elucidates two aspects of materialist theory which had underpinned Marx and Engels’s thinking since the mid-1840s. First, it argues that humanity’s separation from nature is not inherent to the human condition, but rather that humanity is a part of nature; furthermore, human agency in physically reorganizing nature is part of a long historical process, whereby the physical material of nature is incorporated into human systems of value through labour. Engels uses this framework to suggest that humanity must transcend the ecologically destructive patterns of capitalism, and progress to a mode of production that operates in harmony with nature.