Rapid accumulation of pollutants and waste has resulted in a persistent demand for environmental clean-up through sustainable microbial technologies that combine biodegradation with bioenergy generation. Biohydrogen has emerged as a popular biofuel because it produces zero-carbon emissions and is environmentally friendly. This volume in the Wastewater Treatment and Research series delves into the various ways in which biohydrogen can be produced. This includes photosynthetic biohydrogen production, where cyanobacteria decompose water to hydrogen under anaerobic conditions using photosynthesis, anaerobic dark fermentation where hydrogen is produced by decomposition of organic matter by anaerobic microorganisms, and light and dark fermentation. With special emphasis on cell immobilization strategies, membrane processes, and nanomaterials, this book also highlights recent innovations in biohydrogen production such as culture enrichment, pretreatment of wastes, metabolic and genetic engineering, and the coupling process of light and dark fermentation. By providing an ecofriendly roadmap to turning waste into bioenergy, this book serves as an instrumental guide to averting one of the most pressing environmental crises of our times. Professors, researchers, students, and science enthusiasts will appreciate this holistic overview of biohydrogen production, especially in terms of its long-term viability, cost, and environmental implications.