In the 1946 reprint of Brave New World, Aldous Huxley adds a foreword in which he discusses his novel. Huxley feels that a major defect in the work was that he limited the Savage to only two choices at the end, an insane life in Utopia or the life of a primitive in the Indian village. The choice is between insanity or lunacy, and the Savage finishes by choosing insanity, ending in his despairing suicide. Huxley feels that the choices are too limiting, and that sanity should be an option via "a society composed of freely co-operating individuals devoted to the pursuit of sanity."
Huxley also comments on the lack of scientific marvels. Several critics had complained that even though the concept of nuclear fusion as a power source was well known, the novel never mentions this process. Huxley explains the omission with a powerful quote, "The theme of Brave New World is not the advancement of science as such; it is the advancement of science as it affects human individuals."
This distinction is important in Huxley's world because it helps to frame the genre of his fiction. Huxley's work is not strictly science fiction, which includes such classic works as Mary Shelley's Frankenstein and the works of H.G. Wells, and which often depicts how technology can turn against those that create it. Huxley's novel, however, focuses on the ways in which human nature is to use their intelligence to control each other through science. These themes separate the genres of dystopian literature from pure science fiction, though the genres necessarily overlap.
Another marker of dystopian literature is its use of political allegory. Aldous Huxley concludes his notes with a discussion on totalitarian governments. His vision of the future is a world in which authoritarian regimes dominate the realm of real world politics. He asserts that the goal of totalitarianism is to make people love their servitude. In the novel, the state ensures happiness through the caste system and a sense of belonging to the right place, with the help of government-regulated genetic engineering.
Huxley offers several necessary steps for totalitarian control, including an improved technique of childhood indoctrination, a developed science than can place each individual into the proper societal role, a narcotic that is less harmful but more powerful than heroin, and a "foolproof system of eugenics," which he implies will take much longer to achieve than the previous three steps. One can view Brave New World as this sort of totalitarian state, projected six hundred years into the future.