Microbes are the part of our lives in more ways than most understand. They have shaped the present environment and their activities will greatly influence our future. Microbiology is one of the most applied of all the biological sciences. In fact, microbiology is the branch of biology that deals mainly with the study of microscopic organisms called microbes, which are composed of only one cell. Agricultural microbiology is a branch of microbiology dealing with plant-associated microbes and plant and animal diseases. It also deals with the microbiology of involved in nutrient transformation process, decomposition of resistant components of plant and animal tissue, role in microbial antagonism, participate in humus formation, predator to nematodes, surface blooming reduces erosion losses, improves soil structure and maintenance of biological equilibrium.

The book has been prepared in view of ICAR syllabus. The chapters include: History of microbiology, Metabolism in bacteria: ATP generation, Chemoautotrophy and photoautotrophy, Respiration in bacteria, Bacteriophages, Viroids and prions, Bacterial genetics, Genetic recombination, Genetic engineering, Plasmids and episomes, Genetically modified organisms (GMO), Soil microbiology, Microbial transformation of carbon, Microbial transformation of nitrogen and biological nitrogen fixation, Microbial transformation of phosphorus and sulphur, Microflora of rhizosphere and phyllosphere, Microbes in composting, Microbiology of water, Microbiology of food, Food preservation, Biofertilizers, Microbial insecticides/pesticides, Microbial agents for control of plant diseases, Biodegradation, Biogas production, Biodegradable plastics, and Plant-microbes interactions. 

The book will meet out the demand of the students of agriculture and biological sciences. I am sure the teachers and students will be benefited. This is book is not a definitive treatise; its a portrait. Suggestions for the further improvement of the book will be appreciated.