The book "Biological Nitrogen Fixation, Sustainable Agriculture and the Environment" documents the proceedings of the 14th International Congress on Nitrogen Fixation, which took place in 2004 in Beijing, China. It brings together contributions from scientists from over 30 countries who gathered to discuss advancements in research on biological nitrogen fixation and to exchange ideas. This collection reflects significant developments in a field that is crucial for sustainable agriculture and environmental protection. Given the challenges posed by a growing global population and limited agricultural land, the discussion of innovative approaches to improving agricultural productivity and sustainability is particularly relevant. The book offers valuable insights into the latest scientific findings and their practical applications, making it an important resource for professionals and students in the fields of agricultural sciences, environmental sciences, and related disciplines.