Responding to the sustained interest in and controversial discussion of the prospects of hydrogen, this book strives to reflect critically on the perspectives of a hydrogen economy in light of the global energy challenge, in particular the question how to meet the growing demand for transport energy in the long term and how to secure sustainable energy for transportation. This book stands out from other publications by its emphasis on setting the scene for hydrogen and the comprehensive coverage of all aspects related to the hydrogen subject, that is technical, environmental and socio-economic, and with a global geographic scope. The aim is to provide a reference book and compendium about hydrogen that should be of interest to anyone who wants to catch up on the status of the hydrogen discussion, look up a specific aspect related to hydrogen, or understand how hydrogen comes off compared to other mobility solutions. The book should appeal to a fairly broad readership: academia, policy makers and industry.