The universe is suffering with many environmental problems such as global warming, greenhouse effect, etc. The environmental problem is caused by fossil fuels used in vehicles and unwanted industrial gases etc. Therefore, for welfare of the future generation to lead better and healthy life, the research community is in a role to find out newer energy carrier / source for alternating the fossil fuels. The scientific community felt that hydrogen is the best for such applications by refining its limitations such as cost, safety and other technical problems. However, beside the difficulties related to hydrogen production, efficient high capacity storage is still to be developed. Hydrogen can be stored as a compressed gas, liquefied tanks or absorbed in solids. Storing hydrogen in either compressed gas or liquefied tanks is not safe and cost effective. It is succeeded to store good amount of hydrogen in the form of metal hydrides. The book is mainly focusing on development of nano / amorphous structured magnesium based multicomponent alloys by mechanical alloying in order to understand the electrochemical behavior.