Here's a synopsis, so that you can decide whether you want to read the book, and so that debate can ensue here regardless of whether or not you've read it.
The Christian outlook says that man is the ideal being. That is because God incarnated himself as man. This is the anti-transhumanist message of Jesus Christ. Christianity claims that men are already gods in Christ; transhumanism seeks some form of "godhood" outside the Christian vision of Jesus. In this way, transhumanism is more radical than meets the eye. In rejecting mankind, the transhumanist must reject Christianity.
But Christian ethics, and the notion of an unchangeable "human nature" at the heart of existence, are the basis of much of our moral thinking. Without human nature, secular humanism is set to fall, as well as the political notion of "universal human rights."
The non-Christian transhumanist thus faces a difficult metaphysical and ethical problem, because he must grapple with the moral question of how to direct human evolution, yet he cannot appeal to "human nature" to ground his ethics. Nietzsche's notion of the "Ubermensch" is helpful here. But modern materialism and nihilism make the ethical direction of transhumanist evolution difficult. I argue that the notion of "enhancing" humanity is not well-defined, and advocate a more philosophically sophisticated idea of what it means for a species to "advance."
Without some notion of the "Logos" to guide human change, transhumanism is doomed to build on sand. I discuss what a non-Christian Logos might look like – perhaps it is Hermetic, or Hegelian. I argue that transhumanist innovation threatens to fragment human discourse, so that warfare over the reevaluation of values ensues. There may just be no "talking out" our differences with the cyborgs, and physical conflict may be a deciding factor in transhumanist evolution. This is the sense in which Nietzsche foresaw wars on the way to the Ubermensch.
Yet physical conflict may be guided by a non-Christian Logos, or Natural Law of evolution. The outcomes of transhumanist warfare may be decided by the superiority of values, virtue, or wisdom. Indeed, armies thrive on their virtues, and Providence awards victory to the morally worthy. In this way, transhumanist physical or caste warfare is not a chaotic evil but proceeds according to Law, being generative of moral complexity.
Importantly, I argue that contemporary transhumanism is too fixated on technology, and not enough on spiritualism. I foresee the next era as more spiritualist, in line with the notion of the "New Age," and Crowley's notion of the "New Aeon." A holistic vision of human evolution must entertain mystical innovation just as much as technological innovation. But contemporary transhumanism is almost totally guided by technological considerations. This must change if we wish to attain true godhood outside Jesus Christ.