Is it acceptable from an ethical point of view to use stem cells from human embryos for scientific research and clinical therapy? And what are the weaknesses and strengths of various opinions and positions when they are critically evaluated? These are the main problems dealt with in this book. The various chapters as a whole give a comprehensive, many-sided and balanced discussion of the subject. The book contains contributions from biological, medical, social, political, philosophical and theological perspectives. The authors have been chosen because of their professional competence, many of them being respected scholars on a top international level. They give an updated contribution from their own discipline in order to enlighten the different aspects of the common theme. The authors cover various positions and evaluations with regard to the question of the use of embryonic stem cells for research and therapy. The book is written for several audiences: a) scholars and professionals working with stem cell research or with the ethical questions arising from this field (people from biology, medicine, law, philosophy, theology etc.), b) advanced and graduate students within the same professional disciplines and c) politicians and the general public interested in the burning ethical problems which are intensively debated in many countries.