This book is about the role played by microbes in their community mode in sustaining ecosystems. The descriptions given in its chapters indicate clearly that microbial communities are more effective in delivering multifaceted benefits to the soil-plant system than those offered by microbial monocultures in planktonic modes. The role these communities play in a multitude of microbe-microbe and plant-microbe interactions have not yet been fully exploited to gain benefits in this field as well as to achieve sustainability in agriculture practices. Amply discussed are the beneficial characteristics and metabolic capacities of specific microbial groups and the use of microbial traits for the benefit of plant growth.  The book suggests the need to develop new microbial technologies to utilize plant-associated microbes for increased crop productivity and agroecosystem balance in order to ensure sustainability. This also provides an effective guidance to scientists, academics, researchers, students and policy makers of the sphere to achieve the above outcomes.