This book highlights progress in the development, demonstration, and commercialization of hydrogen and fuel cell technologies, with special emphasis on how federal investment has enabled advances and commercial progress.  It starts with a description of how the US government has invested in various energy technologies. This is followed by a brief description of how fuel cell technology works, its importance in the energy arena, benefits, challenges, and current market status of different applications. The third section starts by explaining the R&D status of hydrogen and fuel cell technologies (such as the decreases realized in technology costs), and then explains how federal investments have enabled pathways to commercialization of these technologies. The fourth section highlights supporting and related policy incentives, after which details of successful case studies of fuel cell technology deployment in the materials handling, back-up power, and combined heat and power areas are provided. The book concludes with a summary of lessons learned, recommendations based on experience, and an outlook for the future relating to the advancement and commercialization of the technology.