Microorganisms are omnipresent and they play an important role in biogeochemical cycling of nutrients. Various beneficiary microbes are used to improve the fertility of soil and hence can be used as biofertilizers. The mass multiplication of these organisms have commercial application and can successfully save the environment from the ill effect of the chemical fertilizers. In addition, these can help in decreasing the cost of production. The present book provides glimpses on the prevalence of beneficiary soil microbes viz. nitrogen fixers. Besides, this book is of immense help to the faculty members and post graduate students related to all the disciplines who are engaged in the teaching/research activities in the area of Microbial Technology.