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. The triumphs of physics, chemistry and engineering are tacitly taken for granted. The only scientific advances to be specifically described are those involving the application to human beings of the results of future research in biology, physiology and psychology. It is only by means of the sciences of life that the quality of life can be radically changed. The sciences of matter can be applied in such a way that they will destroy life or make the living of it impossibly complex and uncomfortable; but, unless used as instruments by the biologists and psychologists, they can do nothing to modify the natural forms and expressions of life itself. The release of atomic energy marks a great revolution in human history, but not (unless we blow ourselves to bits and so put an end to history) the final and most searching revolution.

The most revolutionary revolution is to be achieved, not in the external world, but in the souls and flesh of human beings. Living as he did in a revolutionary period, the Marquis de Sade very naturally made use of this theory of revolutions in order to rationalize his peculiar brand of insanity. Robespierre had achieved the most superficial kind of revolution: the political. Going a little deeper, Babeuf had attempted the economic revolution. Sade regarded himself as the apostle of the truly revolutionary revolution, beyond mere politics and economics: the revolution of individual men, women and children, whose bodies were henceforward to become the property of all and whose minds were to be purged of natural decencies, all the laboriously acquired inhibitions of traditional civilization. Between Sadism and the really revolutionary revolution there is, of course, no necessary or inevitable connexion. Sade was a lunatic and the more or less conscious goal of his revolution was universal chaos and destruction. The people who govern the Brave New World may not be sane (in what may be called the absolute sense of that word); but they are not madmen and their aim is not anarchy but social stability. It is in order to achieve stability they carry out, by scientific means, the ultimate, personal, really revolutionary revolution.

-Aldous Huxley, in the foreword to the 1946 edition of BNW.

He may have been a Fabian, like Orwell was, but like 1984, BNW is not meant as a manual: It's a warning.