Based on the fact that today's world is rapidly moving towards the increasing population, so providing human food is currently the most important concern of scientists and agricultural researchers, the use of chemical fertilizers to increase agricultural production has been responsible for the supply of agricultural products to date, but due to their negative effects on soil and the environment, it is not wise to use more of these chemical products. Therefore, there is a need for an alternative approach. In this book, the soil microbes and their beneficial effects on plant growth in several chapters, various microbes such as rhizobacteria, AM fungi, Azolla, etc., and the mechanisms used by them to stimulate plant growth were discussed. The potential of these beneficial soil microbes can only be exploited when used in the form of biofertilizers. Currently discussing biofertilizers as a hot topic of the day, and in this book, we have covered chapters on how to prepare, produce, and application this type of fertilizer. The book also discussed advances in biofertilizer production to date. The chapters of this book have been compiled by scientists and researchers.