In a series of meditations on cloning, embryo research, the human genome project, the sale of organs, and the assault on mortality itself, Kass evaluates the ongoing effort to break down the natural boundaries given us and to remake the human body into an instrument of our will. What does it mean to treat nascent human life as raw material to be exploited? What does it mean to blur the line between procreation and manufacture? What are the proper limits to this project for the remaking of human nature? These are the questions we should be asking to prevent runaway scientism with its utopian longings from reshaping humankind in the image of our own choosing. Kass believes that technology has done and will continue to do wonders for our health and longevity and that we have much to be thankful for. But there is more at stake in the biological revolution that saving life and avoiding death. We must also strive to protect the ideas and practices that give us dignity and keep us human. The book challenges us to confront the post-human future that may await us by thinking deeply about the life and death issues we face today.