This book represents my attempt to convey the excitement of cloning and stem cell research to a wide audience while building on a foundation that starts from basic principles. I have tried to write a book that starts from more or less ground zero and works its way up to current advances. I’ve also attempted to keep jargon to a minimum so that readers aren’t always turning to a dictionary to look up definitions. While writing the book, I found that I also had to confront some nonscientific matters. While the new cell biology has incredible promise – biologists are developing tools to offer some extraordinarily useful therapies – some in the public are wary of its power. They fear a slippery slope. They claim that the scientific community is “playing God”. They bring up deep ethical and moral issues and pose profound questions like “When does life begin?”. While they’re not a major focus of the book, I have tried to address some of the major controversies with as little prejudice as I can muster.