This book is a novel attempt that describes the fundamental aspects of biohythane production technology and advances made in the field. It is a comprehensive collection of chapters based on the fundamentals of heterotrophic hydrogen production and consequent methane production process technologies. It emphasizes the integration of the two stages of the hybrid system for maximum gaseous energy generation from organic wastes, thus making the overall process economically viable. The book gives readers an insight into the technological advances achieved in the field of biohydrogen and biomethane production and challenges involved in the integration of these two technologies. It includes the details of microbiological, biochemical, and bioprocess aspects related to the biohythane process and also discusses the applicability of this process, cost energy analysis, and related socioeconomic concerns. The text is supplemented by illustrative diagrams, flowcharts, and comprehensive tables.