This book explores the latest information on microbial electrolysis systems (MES) for hydrogen production and provides a comprehensive and technical description of various aspects of biohydrogen in anaerobic fermentation and efforts to maximize their yield at optimum conditions. Recently, MES has become a new research area in chemical synthesis, waste remediation, and fuel and electricity generation. Microbiology-based performance for hydrogen production in MES has become an alternative sustainable green technology for clean energy production. In this context, the book is divided into three parts focusing on the basic concept and fundamentals of the MES system for hydrogen production. The first part discusses various structural components and factors influencing biohydrogen production. In addition, microbes and enzymes responsible for biohydrogen production are also explored with the focus on microbial ecology and enzymology responsible for the breakdown of the complex substrate into simple sugar. The second part shows waste pre-treatment strategies and potential feedstock for molecular techniques for biohydrogen production, highlighting several innovative pre-treatment technologies and biocycling. The part also focuses on issues addressing bioproducts, waste management, and bioprocessing technologies for various feedstocks for biohydrogen production in existing industries in the bioeconomic framework. The last part deals with the progress and development in biohydrogen production in the global scenario in terms of scale-up models and new innovation development. The book is useful for young researchers, scientists, students, engineers, managers, technicians, and government officials working in biohydrogen production and waste management.