This book compiles the fundamentals of biohydrogen production technology. It offers comprehensive coverage of microbiology, biochemistry, feedstock requirements, and molecular biology of the biological hydrogen production processes. It also gives insight into scale-up problems and limitations. In addition, the book discusses mathematical modeling of the processes involved in biohydrogen production and the software required to model the processes. It also summarizes research advances, discusses bottlenecks of the various processes, and covers the process economy, policy, and environmental impact of this technology.