This book provides a distinctive introduction to the soil fertility management knowledges and techniques required in the Biological Nitrogen Fixation. The strength of this work accrues from careful and clear Agronomic explanation and detailed coverage of all the necessary topics. It is the first known treatment in such a self-confident form. It requires no previous knowledge of microbiology, and is equally suitable for students in other disciplines needing microbiology, agronomy and soil sciences at this level.