Radical enhancement would employ technology to extend human capacities far beyond anything yet seen or experienced. Imagine, for example, easily outrunning any Olympic athlete while being dramatically smarter than Albert Einstein. Or imagine living for hundreds or thousands of years, making today's super-centenarians seem like mayflies. Soon - perhaps some time this century - we may have the technology for this. But if we had it, should we use it? Radical enhancement might seem like a gift, but could it become, as its critics warn, a poisoned chalice for individuals and a curse for human societies? In this fascinating book, Russell Blackford examines the pros and cons, bringing good humour, philosophical insight, and historical perspective to this most modern of modern debates.