Kropotkin began to write about Russia at length only in the late 1890s, when he published the Memoirs of a Revolutionist and Ideals and Realities in Russian Literature. During the same period, Kropotkin began working on the theory of mutual aid. As he explained in the posthumously published Ethics, one of his key concerns was to address the failure of nineteenth-century science to present a compelling ethical theory capable of explaining the natural origins of moral instincts and providing criteria for judgement. Kropotkin turned to Darwin's theory of evolution to frame his own conception and in the early formulations of the theory of mutual aid, he looked closely at the work of T. H. Huxley, whom he associated with the popularisation of Social Darwinian doctrines. Kropotkin set out to refute Huxley's description of nature as red in tooth and claw in order to also reject Huxley's conclusions: that the basis of morality could only be found in the divine, not the natural world.

Kropotkin continued to work on the theory of mutual aid until he returned to Russia in 1917 and the arguments became very technical, resulting in the rejection of Darwin's Malthusian assumption of scarcity, a Lamarckian interpretation of Darwin and a speculative discussion of biological transmission, supporting Kropotkin's thesis that environmental adaptations could be inherited, and his claim that Darwin also adopted this view. Yet Kropotkin's motivation to set out an anarchist ethical theory was political. He had already presented the substance of the historical account of ethical development that appeared in Mutual Aid in the 1880s. His decision to return to and elaborate this work was made in the context of his growing concerns about the hold that Nietzschean ideas seemed to be gaining within the anarchist movement. In Kropotkin's view, the negative influence of Nietzschean philosophy helped explain the disastrous turn within the anarchist movement to terrorist violence and it created a wrongful impression in the public mind about the relationship between anarchism, nihilism and violence.

When Kropotkin decided to include an account of nihilism in his autobiography, the death of his friend Stepniak (Sergey Mikhailovich Kravchinsky) in 1896 particularly prayed on his mind.