This book provides a comprehensive overview of different agriculturally important microorganisms and their role as plant biostimulants. Arbuscular Mycorrhizal Fungi, Trichoderma, Cyanobacteria, Endophytes, and Plant growth promoting rhizobacteria have the potential to promote plant growth, disease management, nutrient acquisition, stress alleviation, and soil health management. Presenting an all-inclusive collection of information, this book will be important for students, academicians, researchers working in the field of sustainable agriculture, microbial technology, and biochemical engineers. It will also be of use for policymakers in the area of food security and sustainable agriculture. - Introduces new microorganisms as plant biostimulants. - Describes potential mechanisms of plant–microbe interaction for stress alleviation and crop improvement. - Provides information about different microbial formulations (consortium) and their application to the alleviation of different abiotic stresses (salt, drought, nutrient deficiency, heavy metal, etc.) in plants. - Discusses about psychrophilic microbes, endophytic microbes, and total plant microbiome and their uses as biostimulants for improving plant health.