In the early twentieth century, The Iron Heel was an enormously influential book which served as a prototype of dystopian literature. In it we can see the roots of Yevgeny Zamyatin's We, Aldous Huxley's Brave New World, and, most significantly, George Orwell's 1984.

London describes a near future in which pre-emptive action is taken by the owner class against an incipient proletarian revolution. The owners create a caste system in which they, now called the Oligarchs, have established a dictatorship of laissez-faire capitalism. This is especially significant because it's different from or even contrary to the scenarios in subsequent dystopian fiction and in the actual dictatorships of the twentieth century in the Soviet Union, Nazi Germany, and Maoist China, which all overthrew the capitalist system and established allegedly purely socialist states. London's theme in The Iron Heel is that capitalism is by nature undemocratic and is destructive of man's rights and that it is inevitable that the capitalist-owner class will at some point consolidate its power and reduce the working class (and the rising middle class, to a lesser extent) to a condition of semi-slavery.

The novel is written as a kind of frame story in which the memoirs of one (a woman named Avis) who opposed the Oligarchs' takeover are being reviewed and commented upon by a later editor. We are told that in a future day the dictatorship will have been defeated and replaced by a democratic socialist society, the Brotherhood of Man. Thus London's theme is one of ultimate optimism. Unlike Zamyatin, Huxley, and Orwell, whose dystopias end tragically, London believes that after centuries, the Oligarchs' system will ultimately fail. It's interesting, however, to compare London's predictions with those of the other writers in terms of actual results in the century or more since London's death. The Soviet and other totalitarian socialist regimes all fell or were altered beyond recognition into something perhaps resembling London's scenario more than that of the other writers. Communist China has become essentially a dictatorship in which capitalism is permitted and supported by the regime. With the fall of the communists in Russia, a new class of owner elites took over, with an authoritarian leader allied with them. And in Russia, these men were actually referred to as oligarchs, just as in London's novel. This may have been simply because the term oligarchy has been in use for 2500 years, going back to ancient Greece, and of course much more recently was a favorite term of Marx. However, Jack London has been much read in Russia, and it's possible his use of the word influenced those who so labeled this nouveau-riche owner class in the new Russia.