What is cloning and why is the idea of it so disturbing? Why has the birth of Dolly the sheep provoked such furious debate through the world? In a retitled and revised edition of his Wonderwoman and Superman, John Harris looks at the ethical issues surrounding the revolution in biology which has provided scientists with an unprecedented ability to control human evolution. From designer babies to genetic screening by employers, his book provides a stimulating introduction to the present concerns about the rapid pace of developments in human biotechnology.