This book is meant to provide an in-depth understanding of the molecular biology of selenium and how this element makes its way into protein. Selenium is an essential trace element in the diet of humans and many other life forms. It plays an important role in preventing certain forms of cancer, heart disease and other cardiovascular and muscle disorders. Evidence points to numerous other health benefits including an indispensable function in development, male reproduction and the immune system. In addition, selenium serves as an antiviral agent and may delay the onset of AIDS in HIV positive patients and delay the aging process. The emphasis of this book is on the current status of the molecular biology of selenium. The importance of this element in human health is also highlighted. Features the many new discoveries have occurred since the 1st edition on Selenium was published in 2001 New investigators who have made important contributions to the field have been added as chapter authors