The development of biotechnology has produced nothing short of a revolution, both in our capacity to manipulate living things from single plant cells to human nature itself, but also to manufacture brand new life forms. This power to shape and create forms of life has sometimes been described as the power to play God and this book is about the ethics of playing God in the field of biotechnology. International scholars cover moral dilemmas posed by biotechnology, from the smallest cells through animals to the engineering of human beings.