Very good collection of essays. I like the idea of contrasting ideas in a single book, and Savulescu does just that. Oh, and his is one of the excellent essays in this. Anyone interested in the sociological, moral and technological implications of the merge of humans and machines should have a peek at these essays.
I guess being a college philosophy text, it can argue the morality of what is already happening to any human that can afford to modify his or her mental or physical condition. I was not so much impressed with the reality of the issues the book implies but the fuel for science fiction is fabulous.