Since the beginning of human existence on earth, human life has been dominated by the need for energy. Over the past centuries, the world has witnessed several energy transitions. Presently, issues such as energy security & sustainable development are the main driving factors for a transition to clean energy systems. One of the ways to achieve the new desire for energy transition is the use of fuel cell technology. Worldwide, a number of research groups in universities, research centres & private companies are conducting research on fuel cells with an aim to develop & commercialize the technology. This book contains a comprehensive overview of basic & applied research findings on low temperature PEM-based fuel cells. It discusses in details, research activities on individual components & materials development such as membranes, electro-catalysts, MEA & bipolar plate fabrication, single cell, stacks & complete system assembly. It also presents an elaborate discussion on hydrogen & methanol production, storage & delivery. The book is an important reference material for students, researchers & manufacturers involve in research & development of low temperature PEM-based fuel cells.