Addressing a key issue related to human nature, this book argues that the first-person experience of pure consciousness may soon be under threat from posthuman biotechnology. In exploiting the mind's capacity for instrumental behavior, posthumanists seek to extend human experience by physically projecting the mind outward through the continuity of thought and the material world, as through telepresence and other forms of prosthetic enhancements. Posthumanism envisions a biology/machine symbiosis that will promote this extension, arguably at the expense of the natural tendency of the mind to move toward pure consciousness. As each chapter of this book contends, by forcibly overextending and thus jeopardizing the neurophysiology of consciousness, the posthuman condition could in the long term undermine human nature, defined as the effortless capacity for transcending the mind's conceptual content. Presented here for the first time, the essential argument of this book is more than a warning; it gives a direction: far better to practice patience and develop pure consciousness and evolve into a higher human being than to fall prey to the Faustian temptations of biotechnological power. As argued throughout the book, each person must choose for him or herself between the technological extension of physical experience through mind, body and world on the one hand, and the natural powers of human consciousness on the other as a means to realize their ultimate vision.