Why do children look like their parents? Why are some people blond and others brunette, and where do we get our eye colour from? This book explains genetic theory, what genes are, why DNA plays an important role and what all these insights have to do with a curious monk. An exciting journey through the history of science, present-day genetic research and engineering and right through to the question of identity - because who would have thought how much of our personality is defined by our genes and how interesting genes can be?