Biogas is a renewable energy resource that can be an alternative solution for the world's insatiable energy demands while helping in managing waste and reducing the greenhouse gas (GHG) emissions. It is also regarded as carbon neutral as the carbon in biogas comes from organic matter (feedstock) that captured this carbon from atmospheric CO2 over a relatively short timescale. This book has been written and compiled to collate latest information on biogas technology to help readers, researchers and extension workers alike to understand the fruitful exploitation of the process. It has fourteen chapters, primarily in three major categories: 01. the first category dealing with the basic biomethanation process including its ecology, microbiology, biochemistry and molecular biology. 02. the second category dealing with the evolution of the technology in Indian/global scenario from the lab to the land 03. the last category is dealing with the economics of the technology. All the various known and active names in this field of research and development have put their hearts and minds into their contributed chapters. The additional details provided in the Annexures (viz., Model bankable scheme for biogas commercialisation venture; Frequently asked questions in adopting biogas technology; Common terminologies in biogas research; Glossary of abbreviations and symbols frequently used in biogas research; and Prominent global entities in biogas R&D and commercialisation) double the usefulness of the compilation.