Although we often search social and historical documents for clues to our past, biological "documents" perhaps hold the most important evidence of our heritage. The traits we inherit from our parents and pass on to our offspring are encoded in our genes and DNA and reveal much about both our origins and our future. This volume examines the fascinating biology behind genetics and genetic disorders. It also carefully considers the principles of gene manipulation and genetic engineering whose potential to revolutionize medicine, industry, and agriculture is becoming increasingly evident with every new discovery.