The Olympic authorities may ban Oscar Pistorius from competing because his carbonfibre lower limbs give him enhanced power over athletes with the traditional two fleshand- bone limbs. Is this a technical argument, or a deep philosophical and theological issue that begins with trying to establish exactly what it is to be human and then moves to look at whether adding technological fixes causes a radical change?

Future Perfect? is one of a growing list of books delving into this issue. A collection of essays, it benefits from having some chapters that are better than others. The general health warning for any reading in this area is seeing how quickly the author slips from the possible to the most unlikely. I only got to page two of the introduction before reading 'We may be entering a new phase of human evolution'. The next paragraph contained assumptions that this new era is already here! In contrast, I enjoyed Søren Holm's dissection of poorly constructed arguments. This book is not light reading. However, if you want to be challenged to think harder about what it is to be a human being, and want to see some other good thinkers struggling with the problem, then it is a good, if expensive, foil.