London wrote The Iron Heel based on his own experiences and his wide reading. His formal education was minimal; nevertheless, he read such serious authors as Ernest Haeckel, Charles Darwin, Herbert Spencer, Frederick Nietzsche, and Karl Marx, from whose works he derived his own philosophy. When he wished to insert in The Iron Heel historical incidents such as the Paris Commune of 1871 and the Russian Revolution of 1905, he researched them. Finally, he took certain ideas from contemporary popular fiction, notably Edward Bellamy’s Looking Backward, 2000-1887 (1888), Ignatius Donnelly’s Caesar’s Column (1891), and H. G. Wells’s When the Sleeper Wakes (1899).
The Iron Heel ought not to be judged in terms of realism, because it shapes itself into a heroic romance endowed with the contradiction of a Marxist dialectic, an apocalyptic vision of Christianity, and the pains of martyrdom of Social Darwinism.
Critic Charles N. Watson, Jr., rightly judges The Iron Heel to be a “minor revolutionary classic” instead of a major one. It is, Watson argues, a novel “that London seems to have written too much out of his heart, too little out of his head.” Watson keenly points out one of the novel’s most serious flaws: that of the double characterization of Avis. Watson says boldly that London asks his reader “to accept the existence of two Avises simultaneously—the fluttering young woman of the love adventure and the hardened revolutionary of the political drama.” In the long view nevertheless, The Iron Heel offers a reader an imaginative prediction of some of the most important events of the century. Indeed, that expert on the Russian Revolutions of 1905 and 1917, Leon Trotsky, rendered The Iron Heel high praise as a work of imagination.