Magnesium alloys have always been attractive to designers due to their low density, only two thirds that of aluminium. This has been a major factor in the widespread use of magnesium alloy castings and wrought products. The present book gives us an overview in some special areas of magnesium alloys concerning technological applications and eco-friendly requirements. Each chapter brings us a new facet relating to the application of magnesium alloy including, as an example, researches with rare earth metals as alloying components in magnesium implants for orthopaedic applications