The book is written by a scientist, Ian Wilmut, who led a group that created that famous sheep, Dolly. Roger Highfield is a journalist and a science editor of the Daily Telegraph, so he helped the scientist to make the book readable. The book tells how the Dolly was cloned and discusses the technical and ethical problems of today genetics engineering and cloning of mammals, human embryos and humans. It is addressed to a general audience and no special education is required.